Footnote:[2]The observer had used an 8-1/2″ reflector, however, for some years.
Footnote:
[2]The observer had used an 8-1/2″ reflector, however, for some years.
(Another Letter from the same Gentleman.)
Bolton,
December, 1877.
Dear Sir,—As to the adjustments of the 8-1/2 in., I have had very little trouble, and I have tried it again on a few objects, a few nights ago, and with a 7 in. stop, and a power of 300, I split Zeta Cancri and the close doublesfCastor; with the full aperture they were very easy. I have also split Gamma Andromedæ with 7 in. stop, and on a very fine night. I believe 6-1/2 in. would do it.
I just got a look, on November 7th, at the shadow of Titan, on Saturn’s disc; but was driven inside before I could observe the time of its passing the centre. I have seen the Moon on two occasions with the finest definition I ever saw. Altogether I am highly pleased and proud of my telescope. I have not yet tried many faint objects; still I saw the Crab nebula in Taurus much nearer Lord Rosse’s drawings than Herschel’s, as given by Chambers.
I am, dear Sir,
Yours truly,
(Signed.)
Mr.G. Calver.
FromG. Billington, Esq.
Wellwick, Wendover,
July 19th.
Dear Sir,—I am perfectly satisfied with the mirror, a 6-1/2 in., now that I have tried it withyourflat, and I have no difficulty in seeing star disks when the air is good.
I am, dear Sir,
Yours truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. S. Tomlinson.
Carlisle Terrace, Malahide, 1877.
Dear Sir,—I write to tell you that I was very much pleased indeed with last night’s observations with your 18″. The star disks were good and well condensed, and stray light well gathered in, and when a good night comes I have no doubt of it.
The markings on Mars were well defined. I find the advantage of a large aperture shows itself. I have no doubt I picked up the outer Satellite, but cannot be certain till to-night, if I am permitted to see it. The only objection I have is its short focus, as it seriously complicates my labours in matching the secondary convexes for the Cassegrain form—if you can help me in the matter of a longer focus; if not I am satisfied and thankful, and must only proceed to the testing process inch by inch.
Yours truly,
(Signed.)
Mr.G. Calver.
From the same Gentleman.
Carlisle Terrace, Malahide,
November 6th, 1877.
My Dear Sir,—I had intended to write to you before, but, from various duties, I have been obliged to postpone it from day to day. I have been working steadily, however, with your 18″, and I like it the more I use it. The figure is wonderfully perfect, and the definition of planetary details and markings most admirable.
On four occasions I have seen the Satellites of Mars; of these I can feel quite certain of two, for it was held sufficiently long to perceive a marked change in position angle. The intensely small companion toa2Capricorni I have well seen, cleanly separated, and that in strong daylight. I am anxious for a good night to attack τ Orionis. During these observations I have been using the telescope as a Newtonion during my work at the convexes; but my labours have been pleasantly intercepted by the magnificent and gorgeous views of the star clusters and nebulæ—more beautiful and startling than I could possibly have imagined, and surpassing far anything I had ever pictured to my mind.
Yours very truly,
(Signed.)
Mr.G. Calver.
FromMajor-General Addisons, C.B.
Melton, 1878.
Sir,—You will be glad, I know, to hear that I had a very satisfactory evening with the 18 in. equatorial yesterday, and the clock kept it in the field without vibration of any sort.
Yours obediently,
(Signed.)
Mr.G. Calver.
FromJ. T. Stevenson, Esq.
Auckland, New Zealand, 1877.
Dear Mr. Calver,—Since writing to you I have been observing with the 6-1/2 in. equatorial telescope, and I have much pleasure in informing you that I am greatly pleased with its performance. The definition of the planets is beautiful.
I am happy to inform you that I have found a most minute crater in Picarda, it is much smaller than the test crater (mentioned in Cel. Obj., byWebb, page 83) in same formation. I wrote to Mr.Webbabout it, and since then I have seen it distinctly; it is another proof of the excellence of your telescope.
Yours truly,
(Signed.)
Mr.G. Calver.
FromJ. C. Harker, Esq.
Kendal, 1878.
Dear Sir,—After four months use of the telescope I had of you (an 8-1/2 in.), I am able to tell you that I am much pleased with its great excellence. The definition of the mirror is very fine, and its performance on the Moon being superb, with so high a power as 700. The stand I find very steady and convenient, and the screw motions very smooth.
I am, dear Sir,
Yours truly,
(Signed.)
Mr.G. Calver.
FromE. A. Fry, Esq.
Birmingham, 1878.
Dear Sir,—I write to tell you that I like the telescope very much (5-1/4 in. equatorial); the mirror is, as you say, a gem, and it is quite a treat to look at the mysteries above. Saturday was a glorious night, though the Moon was rather too bright. Altogether I am quite satisfied with the telescope, and the finish is first-rate.
Yours truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. J. M. Coates.
The Goddards, Moulton, Spalding.
Dear Sir,—I am able to report satisfactorily on the mirror. On Saturday night last I divided μ2Boötis, power 300, with the 8-1/2″.
Yours truly,
(Signed.)
Mr.G. Calver.
From the same Gentleman.
The Goddards, Moulton, Spalding,
January 18th, 1879.
Dear Sir,—I have been waiting for opportunities for testing observations, but there have been few nights when the weather and leisure time have concurred in giving me a chance. However, I can say this much, that in lunar work I have had much pleasure from the excellent definition given by the 8-1/2 in. I had some fine views of Copernicus under high powers not long since, and am anxiously awaiting opportunities for closer study of a particular region.
Yours truly,
(Signed.)
Mr.G. Calver.
FromFrank C. Dennett, Esq.
10, Terminus Terrace, Southampton,
December 10th, 1878.
Dear Sir,—The 5-1/4 in. is beautiful. Last night there was a slight frosty fog, and the air was very very steady, in fact I only remember about one such night since November, 1875. Saturn was sharp and hard, and the shadow of the ring intensely black, with all powers from 168 to 372, and even with 550, obtained by removing the field lens of 372. The very broad polar caps presented a bluish grey, rendered more visible by contrast with a fine penumbral line of a very slightly brownish grey close to the south border of the ring, and which seemed to be diffused on the south border (i.e., the line was diffused). I should fancy the line here referred to was less than 1″ of arc broad; considerably less!
Turning from Saturn, I looked at ε Arietis, the present distance of which is only 1″·17; with all powers, from 213 upwards, the components were visible as two tiny points of light thoroughly divorced, and with 288 power, reminding one of ε2Lyræ, as seen with 120 on a 2-3/4 in. achr., only the discs seemed freer from rings.
Later in the evening, when the definition was more fluttery, η Orionis shared the same fate as ε Arietis, being well separated with the same powers. The present distance of this star is only 1″·12. Recently I divided this star with a 4-1/2 in. stop on the mirror, power 288. I have seen ε Arietis well with the same stop too. I think I have told you before that the 5-1/4 in., with 372 power, was successful in dividing ε Equulei, whose distance is only 0″·97. This is the closest star I have yet divided.
The Moon is fine too! Last night I caught a large ring close to the terminator, near the south pole (for the Moon was only about 2-1/2 hours past full), which was looked at over the northern wall; the view was beautiful, such gradations of light and shade, interspersed with greys of different hues, which render the object scarcely describable. The finest clefts and tiniest craterlets are rendered visible. It is a puzzle to me how anyone in the possession of £16 or £17 can go buying a refractor of from 2-1/2 to 3-1/4 in. aperture in preference to a silvered mirror. It must be from sheer ignorance of the beautiful views given by the latter, which is superior in every way.
I do not think there is any other point on which I need touch now, so I must beg to remain,
Dear Sir,
Yours very truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. Jevon J. Muschamp Perry, M.A., F.R.A.S.
St. Paul’s Vicarage, Alnwick,
December 20th, 1879.
My Dear Sir,—I was very much interested in reading your account of the grinding and polishing of the 37″ speculum, in this week’s E. M., copied from the “Monthly Notices” of the R. A. S. Had I only the wealth of my neighbours, I would give you an order for the largest telescope you could construct. Every really good night gives me some fresh proof of the great excellence of the 6-1/2 in. For instance, on December 15th, I clearlyand steadily sawEnceladus. I could not, of course, have recognized it had it not been that this month’s “Observatory” gave diagrams of the positions of the five inner sats. of Saturn, for 8 p.m. on every day of this month, and a careful search for Encel. was fully rewarded by a clear and steady view of it at that time in its proper place. On this feat the Rev.T. W. Webbwarmly congratulated me, and said that he had seen Encel. with his 9-1/3″ “With,” but only when Saturn was hidden behind a bar. I saw it clearly in exactly its proper positionwithouthiding the planet—power 400. I have also had several good views of Mr.Webb’snew nebula in Cygnus, and have sent him drawings of the field, which he confirms. I have also made some fine drawings of Jupiter and Mars. On December 12th, 11 p.m., I tackled σ 749 (in Taurus), a very difficult test for my aperture, only 0·8″, andperfectlysplit it with power 300. The night was superb. When you consider that the theoretical limit of dividing power for a 6-1/2″ is only 0·7″, I think I have done well to split a star 0·8″ in our climate.
Faithfully yours,
(Signed.)
Mr.G. Calver.
FromG. Ferguson, Esq., M.D.
Altidore Villa, Pittville, Cheltenham,
June 26th, 1879.
My Dear Sir,—I write to tell you that Thursday night being very fine, I had a good opportunity of trying the (an 8-1/2″) mirror on Jupiter, although this planet was lower than it should have been to give the fairest trial. Well, I can only assure you that, despite the low position, I never saw it so beautifully before. The contour of the clouds, particularly one orange one,sf, the delicate lines, and the colouring of the belts, were all seen with a sharpness which I had believed scarcely attainable, and proving that the result of your labours has been to effect a very real improvement in the speculum. Notwithstanding the good planetary definition, the air was not tranquil enough for seriously attacking really difficult doubles; still I was much pleased with its performance on π Aquilæ.
Yours truly,
(Signed.)
Mr.G. Calver.
From the same Gentleman.
July 27th.
Yours of July 25th duly to hand. I have the speculum adjusted in the “pink” of accuracy. Star discs are small and round, with concentric diffraction rings, and quite rayless except in the case of the very brightest stars, and even with these the rays are very trifling. But for the diffraction rings, which I fancy a really good night will mostly get rid of, I should, I feel sure, have readily divided η Coronæ.
The Moon last night, though very low, was seen with most gratifying ease and sharpness. Altogether you will gather that I am more than satisfied. I am greatly gratified, and will look forward to great pleasure as the season advances.
Yours faithfully,
(Signed.)
Mr.G. Calver.
FromThe Rev. Jevon J. Muschamp Perry, M.A., F.R.A.S.
St. Paul’s Vicarage, Alnwick,
August 8th, 1880.
My Dear Sir,—You have indeed surpassed yourself, and your performance is better than your promise. The mirror arrived safely yesterday, and when I unpacked it I was exceedingly pleased with its surface and general appearance, but of course that was a small matter. I waited till night to test it on a close double.
I first tried it on ε Boötis, and although the night was very bad the definition it gave of the two stars with 450 and full aperture was admirable, considering the night. After waiting a long time for clouds to clear away, I turned the tube on that exceedingly difficult test, δ Cygni. I consider this star to be one of the severest tests for any telescope, reflector, or refractor of any aperture in the whole heavens. The performance of the mirror upon it, with thefullaperture, was simplyMAGNIFICENT, the small close companion standing out clearly, well separated from its bright primary, although the night was not good. I hardly thought it possible that the fine 18 inch mirror could be excelled. I am bound to confess that you have excelled it.
To say that I am extremely grateful to you is a very poor expression of my feelings. I am pleased and delightedbeyond measurewith thesuper-excellent18-1/4 in. mirror you have sent me. Clouds put an end to my work last night, but I have no doubt that in the future every night’s observations will only accumulate proofs of the exquisite perfection of your handiwork.
Very faithfully yours,
(Signed.)
Mr.G. Calver.
Extract from the “English Mechanic,” September 3rd, 1880.
“The telescope is a silvered-glass Newtonian reflector. There are two specula, one of 18 in. in diameter, figured by the celebratedWith, in 1878, and is a magnificent specimen of that eminent maker’s handiwork. In fact, I am given to understand that Mr.Cooper Keyconsidered that he had attained perfection in this mirror, and of all men then living there was no better judge than he. The other is 18-1/4 in. in diameter, and was originally figured by Mr.Cooper Keyhimself; but it was only perfect over the interior 14 in., and, consequently, while the whole aperture could be used on the moon and planets, this was all of it that could be used upon close doubles. I determined, therefore, to give this mirror to Mr.Calverto re-figure, and, if possible, excel Mr.With’sspeculum.
“In order that Mr.Calvermight know the extent of his task, I returned home through London and Chelmsford, bringing with me both mirrors, which Mr.Calvertested for himself at the centre of curvature. After the trial was over, he pronounced Mr.With’smirror to be an exceptionally fine one, and heartily congratulated me on the possession of such a beauty. I left the other one with him to be re-figured.
“And now to come to the most important part of all—the performance of the 18 in.Withmirror upon close double stars. Since the telescope came into my possession, I have never had a thoroughly good night; but even on an indifferent one, I have, with thefull aperture, divided such extremely difficulttests as η Coronæ, μ2Herculis, and δ Cygni; and these results were quite sufficient to show me that the very high reputation of its excellent maker is worthily and proudly maintained by this mirror. In fact, the definition it gave one night, when the Scottish Astronomer Royal was staying with me of ε Boötis, was such, that the Professor told me I could not expect any telescope, reflector, or refractor, upon the same object, and on the same night, to do better. However, I knew Mr.Calverwas doing his very utmost in the honourable and praiseworthy competition to attain perfection, to give me a mirror which would bear favourable comparison with Mr.With’s. It reached me about a week ago, and on the same evening I had an opportunity of testing it upon what I consider to be one of the very severest tests that can be applied to any telescope, reflector or refractor, in the northern heavens, that is δ Cygni[3]. To make the test as severe as possible, I applied thewholeaperture at once, with a power of 347. I was surprised and delightedbeyond measurewith the result. The small star stood out clearly separated from its bright primary, and there were two or three diffraction rings round the latterunbrokenin any part, andequallybright all round. I consider the results which Mr.Calverhas attained in this mirror cannot possibly be excelled. I measured this star on two separate nights, and the mean results are pos. 328·9°, dist. 1·29″. I also measured, with this mirror, another difficult star of the same character, namely, with a bright primary and small companion, ζ Herculis, with the following results, pos. 111·3°, dist. 1·03″. I make the companion of this star a dusky blue, or lavender. As regards the light-grasping power of the mirror, I turned it, the other night, on the minute pair between β1and β2Capricorni, which Sir John Herschel gave as the test of the power of any telescope and eye to observe the satellites of Uranus. The night was very unsteady, but the minute stars of the pair were most conspicuous.”
Footnote:[3]Note.—Mr. Perry does not mean that δ Cygni is one of the most difficult tests as regards the distance of the components. He has often seen it with his 6-1/2″ Silvered Glass Reflector, and even with a stop of 5-1/2″ on the same instrument; but he was surprised at the beauty and perfection of the images—perfect and unbroken rings—and he knew that these appearances could not have presented themselves had not thefigureof the mirror been of extraordinary perfection.
Footnote:
[3]Note.—Mr. Perry does not mean that δ Cygni is one of the most difficult tests as regards the distance of the components. He has often seen it with his 6-1/2″ Silvered Glass Reflector, and even with a stop of 5-1/2″ on the same instrument; but he was surprised at the beauty and perfection of the images—perfect and unbroken rings—and he knew that these appearances could not have presented themselves had not thefigureof the mirror been of extraordinary perfection.
FromThos. Westlake, Esq.
Fordingbridge,
June, 1880.
My Dear Sir,—I wrote you last evening, and afterwards had my first trial with the telescope (a 10 in. Alt Azimuth). It turns out a beauty. I had the full aperture on all the evening, the air was very good, but not perfect. Alpha Lyræ was a splendid object with all powers, a most brilliant disk with just indications of circular rings—no wings or rays. I turned it on B Cygni, and the beauty of the mirror stood revealed, both starsperfect disks, withjustthe indication of perfect circular defraction rings, and the colours were most beautiful,—nothing could possibly appear finer. I consider the mirror perfect, and the stand most convenient and smooth and pleasant in action.
I am, dear Sir,
Yours truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. E. H. Lowe.
Wilmcote,
April, 1880.
DearMr.Calver,—I have been exceedingly occupied, as there has been a succession of gloriously fine nights, and I have secured the Nebulæ diagrams I so much wished for Mr.Webb,—and I would allow nothing to divert me from them—but I put it (a 15-1/2 in. equatorial) on Zeta Cancri, and it was shown beautifully. I have been working at the driving clock, and it is under capital control. The great cluster 13 M., is a glorious object, and magnificently resolved. I see all I look for on the Moon.
Faithfully yours,
(Signed.)
Mr.G. Calver.
FromW. Scott, Esq.
Southwick, Sunderland,
July, 1880.
Dear Sir,—Dr. Blacklock, and also Mr. Bell, have seen the mirror, and pronounce it perfect, and it performs admirably.
Yours truly,
(Signed.)
Mr.G. Calver.
FromJames L. McCance, Esq., F.R.A.S.
Putney Hill, S.W.,
October 23rd, 1879.
DearMr.Calver,—Weather and circumstances have been very unfavourable for doing much work with the 10 inch reflector since I got it from you. But with what I have seen with it I am very pleased; in good weather the views of the planets, Jupiter and his “Great Red Spot” especially, were grand. The mounting (equatorial) is quite satisfactory, and the movements work smoothly and well.
Yours very truly,
(Signed.)
FromFrank C. Dennett, Esq.
10, Terminus Terrace, Southampton,
July 11th, 1880.
Dear Sir,—It is a long time ago that you asked me to write and let you know how I liked the 9-1/2 in. I have not done so because I wished first to see what was to be made of the planets.
Last night, at 14h30m, I had my first peep at Jupiter through it, and a grand sight it was; his belts coloured, though not so vivid as they are sometimes, were fine in the extreme; and, though the power employed was only the achromatic 215, the satellites were beautiful little discs, one especially showing the tint of its surface.
A quarter of an hour later Saturn was in the field of view; a grand object, several of the satellites surrounding it. A little cloud was coming up over it, so I could not see so much of this planet as I should have liked, though amply sufficient to prove incontestably its high class.
With double stars I have not attempted much, though on turning it on μ2Boötis I found the division easy, the components being respectively slightly orange, and dullish white or pale yellow.
I have had lots of grand views of the wonders of the “star depths,” clusters, and nebulæ, notably 57 Messier, the Ring nebula, in Lyra, the great Orion nebula, and the marvellous Whirlpool nebula, the chief outlines of which were well shown.
Hitherto the instrument has been chiefly employed on the Moon, the details of which come out hard and sharp in a beautiful manner, with all powers up to 515, the highest I have.
The 5-1/4 in. pleased me very much, but the 9-1/2 in. delights me.
Yours faithfully,
(Signed.)
Mr.G. Calver.
FromG. W. Royston Pigott, Esq., M.D., F.R.S., F.R.A.S., &c.
Eastbourne,
July, 1880.
Dear Sir,—There has been but little weather for testing. Mr. Slack has been staying with me; we are delighted with the 8-1/2″, and think it a great beauty. I can hardly imagine any mirror much better, and I expect great precision from it. I find its focus to be 65 inches, not quite so much as my fine Dollond glass, of 3-3/4 in. aperture.
Yours truly,
(Signed.)
Mr.G. Calver.
FromA. Williams, Esq.
Clarence Lodge, Grafton Street, Brighton,
August, 1880.
Dear Sir,—I had intended writing to you to express my pleasure in my 5-1/4 in. telescope nearly a month ago, but thought I would have another look first, and the more I look the more I am pleased with it. I cannot now imagine anyone preferring a 3-1/4 in. refractor to one of these. I have had no trouble at all with the adjustments, and if was to get out of adjustment, it could be rectified in about five minutes. Notwithstanding the unsettled weather (giving on an average only about one fine night in eight), I have examined nearly two hundred double stars in the last three months, some of them very difficult. I enclose a list of a few, which will show very well the capabilities of the instrument.
Yours truly,
(Signed.)
Mr.G. Calver.
LIST OF OBJECTS SEEN WITH A 5-1/4 INCH REFLECTOR.
ξ Scorpii (5, 5·2 : 1″·3) clearly divided, 186 power.
ε Lyræ. Debilissima quite easy; 186, 380 powers, though nearly half Moon.
μ1Herculis (9·4, 10 : 1″·04). Just divided, 380. Very difficult, owing to its faintness.
Vega. 11 mag., comes quite plain, only 47 minutes before sunrise; powers 110, 186.
φ Virginis (5, 13 : 4″·27). Comes plain, 110, 186.
ν Scorpii, the close pair (4, 5 : 0″·8), well elongated, power 380; small star (7, 8 : 1″·68) divided, 110.
ζ Boötis (4, 5 : 0″·88) elongated 186, notched 380, and with field lens removed, all but divided.
δ Cygni (3, 9 : 1″·63), 9 plain, 380 on several occasions.
Antares is chiefly an atmospheric test, but the companion was quite plain on one occasion out of the three I looked for it.
μ2Boötis (7·5, 8 : 0″·63), considerably elongated, 380.
η Coronæ (5·5, 6 : 0″·62), slightly elongated, 380; but not nearly so much as μ2Boötis.
56 Herculis (6·5, 13 : 15″), 13 easy, all powers.
π Aquilæ (6, 7 : 1″·5). Just separated, 110; 14 mag. (Webb), just visible, 186.
ε Equulei. Just divided, 186 (5·7, 6·2 : 1″·0).
FromD. Traill, Esq.
Balham,
March 5th, 1880.
My Dear Sir,—I have at present to use the telescope, an 8-1/2 in. Alt Azimuth, out of a window, and so at a great disadvantage,—in fact cannot give it a fair trial till I have the house ready for it, meanwhile I use it as occasions offer, and have been highly pleased with it. The views of the nebular in Orion resemble those ofBond’sdrawings, and shows immeasurably above my 3-1/4, of course. I think the mirror isperfectfrom its performance on large stars whose disks are small and round, without rays of any kind. I amthoroughlysatisfied.
Yours truly,
(Signed.)
Mr.G. Calver.
FromHugh Auld, Esq.
Grosvenor Crescent, Edinburgh, 1879.
Dear Sir,—I have not been able to do much with the telescope, a 5-1/4″ Angle-block, through the unfavourable weather for the last four months, but with the opportunities I have had its performance is satisfactory; it performs well on stars with high powers, and I am sure it will bear a good deal higher. I am very well pleased with the instrument.
Yours truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. Thos. H. Browne, F.R.M.S., &c.
The Cedars, High Wycombe,
February 26th, 1880.
Dear Sir,—I am exceedingly pleased with the action of your mirror (an 8-1/2 in. equatorial); what I have seen of sun, moon, planets, and stars is splendid. I have had a good many telescopes, but never liked one so well as the one you have sent me. For the first day or two I could do nothing but admire it.
Yours truly,
(Signed.)
Mr.G. Calver.
FromThe Rev. Conybeare W. Bruce, M.A., F.R.A.S.
St. Nicholas’ Rectory, Cardiff,
July 17th, 1880.
My DearMr.Calver,—You will have been looking for some news of me and the 12″. I have purposely delayed writing until I wasreallyin a position to say something definite, and you had already heard my high opinion of the mirror. Let me at once say that that opinion has beenmorethan justified. The mirror is abeauty. Canon Beechey and I got Jupiter and Saturn at 2.30 a.m. yesterday morning—and they weresuperb. The Canon declared enthusiastically, that he “hadneverseen Saturn anything like that,” and the last thing he said to me on the subject as I parted with him to-day was, “You have got a very fine instrument indeed.”
If Icouldadd anything more in its praise it would be this, that I am really going to build anew observatoryfor it—my present one is too small and cramped.
Sincerely yours,
(Signed.)
Mr.G. Calver.
(Another Letter from the same Gentleman.)
St. Nicholas’ Rectory, near Cardiff,
August 28th, 1880.
DearMr.Calver,—The 12 inch surpasses all my expectations. It has the perfection in figure of the incomparable 10 inch of yours, which was its immediate predecessor, and, in grasp of light, the difference in favour of the 12 inch over the 10 inch, a most brilliant mirror, is simply astounding.
You may equal the 12 inch—I am sure you will, whenever you make one—but you will not easily beat it. Mr.Sadler, the well-known and most accurate observer, has himself worked with it, and writes of it to me as follows:—“The 12 in. is considerably superior in light grasping power to H2’s 20 ft. reflector, and the figure is a much finer one.”
Your skill and kindness has placed me in the front rank among amateur observers, as far as the possession of optical means is concerned.
I was afraid that the German Stand would not prove so convenient as the “Berthon Equestrian Stand,” but I find it is and far more so. The GermanStand is, for anything above 6 in., decidedly more solid and dependable, and far simpler in any case. The merit of the “Berthon Equestrian” form is that it requires a smaller observatory.
Very sincerely yours,
(Signed.)
FromW. S. Franks, Esq., F.R.A.S.
Leicester,
August 19th, 1880.
My Dear Sir,—As the 11-1/4 in. speculum has now been in constant use for two years, I may be allowed to express my opinion, with all due deliberation, as to its performance. It has been tried upon almost every conceivable object during that period with uniformly good results. Having also a 5 in. achromatic of the finest quality, I have been enabled to make a great number of comparisons between the two instruments, mounted side by side: and for fine definition, smallness of star discs, and freedom from chromatism, the reflector always came out victorious. Upon first mag. stars, nothing could surpass the purity of the image in the reflector; but on immediately turning to the achromatic, the outstanding violet rays were painfully obtrusive. For red stars, which are generally small, the reflector seems especially adapted. I used to be rather sceptical about the tints of red stars, but must confess, after seeing the magnificent tints of scarlet and crimson which are shown by a large aperture, that my doubts have vanished. Definition upon the planets, in good air, is simply perfect. The detail on Jupiter and Saturn reminds one of an exquisite engraving. The far distant Neptune is perfectly defined as a tiny disc, and his moon steadily visible with the 11-1/4 in. The faculæ and other Solar detail are brought out with wonderful distinctness. As for the Moon, the crispness of definition, absence of colour, and immense number of minute objects shown by the reflector, leave nothing to be desired. The gorgeous views of clusters and nebulæ: the brilliantly crowded fields in the galaxy: and the endless variety of star colours and groups are almost beyond description, and must be seen to be appreciated. I could fill pages about objects seen with the 11-1/4 in. mirror, but will not occupy more space, save to thank you for having placed such perfect instruments within the reach of amateurs.
Yours faithfully,
(Signed.)
Mr.G. Calver.
FromW. S. Franks, Esq., F.R.A.S.
Leicester,
September, 1878.
My Dear Sir,—Mr.Burnhamis undoubtedly “facile princeps,” as an observer of double stars. Few men could have discovered such difficult objects as he has done with a 6″ O.G. Perhaps, it ought to be conceded that the usual formula for separating power, requires modification in his case, as Pogson’s formula for “minima visible” did with Mr.J. W. Ward, of Belfast. Apropos of this topic: do you recollect Mr.Ward’sdiscovery of several additional comites to Pxx 452 Cygni? One of them Mr.Burnhamonly succeeded in seeing with the greatest difficulty with the 6″ O.G. when the large star was hidden by abar. I can see this easily enough with the 11-1/4 in. mirror, in presence of the brighter star.
When you have any intending customers halting between two opinions, or in any way dubious about reflectors—if you will refer them to me, I shall have great pleasure in giving my testimony. Reflectors have been very badly used, and in justice to them I shall not hesitate to express my honest conviction whenever it is asked.
Yours sincerely,
(Signed.)
Mr.G. Calver.
FromPhilip Vallance, Esq.
Cobb Court,
August 24th, 1880.
DearMr.Calver,—I write to thank you for the very excellent 12 in. mirror you have worked for me. You know that I have excellent opportunities of testing it by those of With, Bird, Grubb, Murrell, and others; and also for definition by a capital 6 in. refractor—and I can truly say it is surpassed by none, and equalled by few: it is quite my favourite instrument, and has been a source of much enjoyment ever since I have had it, and again I thank you for working me such a treasure.
I am, dear Mr. Calver,
Yours very truly,
(Signed.)
FromThe Rev. N. S. Godfrey, F.R.A.S.
St. Bartholomew’s Vicarage, Southsea,
August 23rd, 1879.
My DearMr.Calver,—The 12 inch mirror which you worked and mounted for me gives me perfect satisfaction. I think I have had sufficient experience with telescopes to justify the expression of a confident opinion, as at one time or other I think I have had 13 achromatic telescopes by Tulley, Dollond, Simms, Jones, Cooke, and Murrell, of apertures varying from 2-1/4 to 7 inches, besides 5 graduated instruments. The one I had before yours was an 8-1/8 With-Browning, which With himself considered of as fine a figure as he could work, and it certainly was a beautiful mirror. Your 12 inch is quite as perfect in its definition. I have soon on particularly fine evenings Castor as two discs, without wing or ray. I have separated with ease ω Leonis, μ2Boötis, η Coronæ, γ2Andromedæ, and many others of that class. The planets Jupiter and Saturn on fine nights are magnificent. I could go into more detail, but I think the facts I have mentioned are sufficient to convey an idea of the performance of the mirror; and I am particular in expressing my opinion thus strongly, because great names, with no experience of reflectors, are committed to their condemnation. I am certain that under favourable circumstances they arequiteequal in their performances to refractors. I know my 8-1/8 With was in every way equal to my 7 inch Troughton and Simms, and in light superior, when newly silvered. And when the cost is taken into consideration, Cooke’s price of a 10 inch O.G. being £390, without mounting,and your price for a 10 inch mirror being only £25, I can only express my astonishment that there can exist any doubt in the scientific mind upon the subject.
May I say that I shall be pleased to answer any questions that any of your intending purchasers may wish to ask. I cannot speak too highly of your mirror. I may add that through the courtesy of its possessor,A. A. Common, Esq., I saw Jupiter magnificently last year in the 37″ mirror you worked for him.
I am, my dear Mr. Calver,
Very truly yours,
(Signed.)
FromThe Rev. Canon St. Vincent Beechey, F.B.A.S., &c.
Hilgay Rectory, Downham, Norfolk,
June 22nd, 1880.
My Dear Calver,—I really do not know how to thank you enough for all the pleasure you have given me, and for the excellence of the work you have done for me. I like it more and more! It is really as near perfection as I could ever hope for. Even at my old age of nearly eighty, I divide 1 second stars like two dots, and I used a power of 700 on my 8 foot. What mirror but of great excellence would bear that power, and give you twodots! I would not part with it for anything. When I have been to Mr. Bruce he is coming to me, and we will try your 12″ against my 10″. He will have light, a great thing for me, but I do think hecannothavebetterdefinition. I hope nothing will prevent his getting the 12″ in time for us to adjust and try it. My telescope, now complete, is a gem, and has given me more pleasure than any other scientific thing.
Ever most sincerely yours,
(Signed.)
Mr.G. Calver.
FromThe Rev. J. Gwynne Hughes, F.M.S., &c.
Maldon,
August 30th, 1880.
My Dear Sir,—All my friends are greatly pleased with the 10 in. reflector you have made me—with its general appearance and superior workmanship.
The wheel at the foot adds very much to its portability. Tho form of its stand is the best I have seen, giving a complete sweep without any fresh adjustment. The cell bearing the reflector drops into its place without any difficulty, even in the dark. The trials I have made of the instrument have revealed a clearness and sharpness of definition far superior to anything of the kind I had seen before.
I am indebted to you for a source of boundless scientific interest at very moderate expense. With best wishes,
I remain, dear Sir,
Yours sincerely,
(Signed.)
Mr.G. Calver.
FromWalter Goodacre, Esq.
Seven Sisters Road,
May, 1879.
Dear Sir,—Respecting the 5-1/4 in., I am very much pleased with it; the definition is very good.
As a proof of the excellence of the mirror, I may mention that I have on several occasions seen the small crater on the floor of Helicon, given byWebbas a test for a 9 in. mirror.
Yours truly,
(Signed.)
Mr.G. Calver.
(Another Letter from the same Gentleman.)
FromRev. N. S. Godfrey, F.R.A.S.
October 4th, 1880.
Dear Sir,—I have been able to get to use my telescope again, and send you some of my seeings.
June 17th.—α Herculis. Still night, 10 p.m., light haze. Discs beautifully small. Occasionally without any interference ring.
July 18th.—ζ Herculis. Beautifully seen, power 496, Cooke.
August 16th.—Well seen. 6.15 p.m., daylight.
August 26th.—σ Cygni. Misty. Adjustment beautiful. Small star well seen. ψ Cassiopeæ. Double blue star well divided.
August 27th.—ζ Herculis. Both stars occasionally without ray or ring. Two brilliant dots. Colour of companion, pale lilac. Full aperture. Power 207, Cooke. 6 p.m.
August 30th.—Dumb bell nebula. Well seen. Not at all regular in outline, as given by H. Several glimpse stars.
September 24th.—ζ Herculis. Very fine definition. The difficulty with this star is clearly atmospheric. I saw it well with 8 in. aperture, power 207: but the interference ring became thicker and continuous all round: probably owing to the larger size of my diagonal prism, nearly 2-1/2 in.
The planets are now again simply magnificent. All the usual details I see splendidly with full aperture of 12 in., and as sharp as if cut out with a penknife. The great red spot is a wonderful phenomenon. What is it?
The great nebula in Andromeda, seen through your fine nebula power is a mysterious sight. You seem to be looking at something which eludes your vision (except the nucleus); you see it, and yet, ghost-like, you see through it. I long for the great nebula in Orion. I did not see it last year on account of illness.
Believe me,
My dear Mr. Calver,
Very truly yours,
(Signed.)
Mr.G. Calver.
FromT. Hildersley, Esq.
33, Berwick Street, W.,
September 9th, 1880.
Dear Sir,—I am very pleased to be able to tell you that I have got the 8-1/2 in. mirror into very fair adjustment—only a slight flare on one side, which I could correct if clouds had not come up, and I have not had a chance since, as my time is very limited.
As it was, comes to Wega came out fine; also debilissima, ε Boötis, μ2Boötis, was well seen. Stops made little improvement. Nebula in Andromeda very fine, both large and small. Clusters in Hercules well resolved, and Jupiter and Saturn, though low down, were grand; all is clear with any power or aperture.
Yours truly,
(Signed.)
Mr.G. Calver.
FromRev.E. A. Fishbourne, M.A.
Minor Canonries, Llandaff,
October 4th, 1880.
My Dear Sir,—I send you my cheque, which I do with the greatest pleasure. I am delighted with, the telescope and with its capabilities.
Faithfully yours,
(Signed.)
Mr.G. Calver.
FromWalter Goodacre, Esq.
London, N.,
September 6th, 1880.
My Dear Sir,—The 8-1/2 in. mirror which you supplied me with during the early part of the year, I have recently mounted as a simple equatorial. And although I have had but few opportunities at present of using the same, they have been sufficiently numerous to prove, beyond doubt, the great excellence of the mirror.
On the evening of the 3rd September, I had some beautiful views of Jupiter and Saturn. In the former the deep coppery hue of the equatorial belts, and of the large spot, at present visible on his southern hemisphere, were strikingly conspicuous, as were many minute details of his surface. In the case of Saturn, the gradations of light on the rings, and the delicately tinted belts on the planet itself, also the sharply defined shadow of the planet on the rings were easily seen.
Its definition of the most minute portions of the moon’s surface, leaves nothing to be desired, whilst its performance on double stars is equally satisfactory.
Yours faithfully,
(Signed.)
Mr.G. Calver.
FromG. W. Royston Pigott, Esq., M.D., F.R.S., F.R.A.S., &c.
Eastbourne,
October 4th, 1880.
Dear Sir,—Your figuring of the 8-1/2 in. mirror has given me much satisfaction. I see ε1ε2Lyræ, and such stars, with 600, very sharp and clear.
I have counted six satellites of Saturn, and the equatorial belt is very distinct.
Last week I happened to observe Jupiter, when a black shadow of a satellite was beautifully notching the limb, at the same time a small pearl-like satellite was about to egress from the belts. I saw, also, six spherical cloudlets on the belts.
Yours faithfully,
(Signed.)
Mr.G. Calver.
FromRev. S. Mills, M.A.
Droylsden,
September 4th, 1880.
DearMr.Calver,—To-night was an exceptional fine night for the stars, the like of which I have not had since I got your 6-1/2 in. I had for a week or so been observing with my home-made 8 in., but to-night again recurred toyours, and itssuperioritywas all the moreconspicuousandgratifying. It quitedelighted me afresh!
Looking at β Cygni, I picked up two, to me, new stars, which I think fully completes Mr.Sadler’stests in this field. I mark the newly found ones in red. This only shows that one has only patiently to watch and wait for a suitable observing night to get one out of a certain aperture it is capable of showing.
The vast superiority of your 6-1/2 in.has quite put my 8 inch out of court!!
Yours faithfully,
(Signed.)
Mr.G. Calver.
(From the same Gentleman.)
Droylsden Rectory, Manchester,
July 30th, 1880.
My Dear Sir,—I can scarcely express to you the pleasure I have had in the use of your splendid 6-1/2 in. mirror. Both in light grasping power, and in the separation of close double stars, it has far surpassed my highest expectations, and quite removed the prejudice I entertained against reflectors. Though possessing a first-class 4-1/4 in. refractor, equatorially mounted in my observatory, I now use your mirror in preference, in the more difficult and delicate observations, and with it am able to master the most severe tests given for 6-1/2 in. aperture. I would not be without one of your finely figured mirrors, now that I have tested their merits, for any consideration.
(Signed.)
Mr.G. Calver.
(From the same Gentleman.)
The Rectory, Droylsden,
October 4th, 1880.
My Dear Sir,—I have given your 8-1/2 in. mirror one night’s trial, and it has greatly pleased me. Its resolution of the great cluster in Hercules was truly magnificent, and the clearness with which it brought out stars very difficult with 6-1/2 in. was highly gratifying. I hope to turn it to very good account.
Yours faithfully,
(Signed.)
Mr.G. Calver.