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Of course Mark also collected and restored a large collection of instruments manufactured by the Hysom brothers’ firm AE between the 1960s and 80s. This included a 10″ Relay-lens Dall-Kirkham Cassegrain that I used to use (I described this instrument in JBAA 2007 April) that was also reputedly part-made by Dall. I don’t know if he still has this curious collection.
There seem to be two issues here: weight (back problem) and setup time.
These are common problems. I deal with them in my book ‘Setting-up a Small Observatory’ (Springer), and we’ll deal with them again at the Equipment & Techniques Section meeting on 17 November.
I think you have 6 general choices, which address, or not, the two issues, in different ways:
- Leave the tripod and wedge outside, polar aligned, cover it with some sort of cover, and just move the telescope and other equipment in and out each night (may not address weight problem)
- Leave the telescope and tripod outside and cover it with some sort of cover or box, either flexible or rigid, that is completely removed when you observe (might address both problems)
- Build a proper observatory (addresses all problems in the long term, but may be difficult or expensive)
- Get a system that breaks down better into lighter components, maybe tripod, German equatorial mount with dovetail fitting, and optical tube (may not solve setup time problem)
- Get a smaller telescope (solves most problems, but not good for planets)
- Get a tracking alt-az or Dobsonian system (may not solve weight problem)
Damian Peach seems to leave his C-14 outside most of the time, just covering it over with a fabric cover, and it survives. In my experience this method results in corrosion, however, and of course you’ve got a big security problem. You still need to disconnect and take in all the camera etc. More of a proper shelter or box, such the one Richard Miles built, is better. This kind of solution, if well done, allows you to leave everything outside, including cameras, power supplies and wiring, and this saves an immense amount of time.
Nothing really beats an observatory for time-saving and back-saving convenience, and at the meeting on 17 Nov I’ll be describing a ‘An observatory from a £100 shed’.
But going back a stage, without building anything, you do mention polar alignment taking ‘impossibly longer’. Imaging planets does not require very accurate polar alignment, so I wonder if you are making too much of a meal of this. Increasingly also people are using the new CMOS-based cameras from companies like ZWO and Altair to do deep sky imaging in a more ‘planetary’ manner, using stacks of short exposures (1-10s). Then they really don’t need accurate polar alignment at all. In fact planetary imaging, and this sort of short-exposure imaging of brighter deep-sky objects, is possible with the tracking alt-az or Dobsonian system I mention as option 6.
There’s a lot to consider, and in the end only you can tell what your best convenience/performance/expenditure compromise is.
David
Director, Equipment & Techniques Section
The night after my previously reported observation, on February 22, I managed to get my C-5 (127mm SCT) mounted where I could get Sirius with it. I first had to cut down much of a giant weed in my elderly neighbour’s garden, that was in the way. I seem to do most of my gardening at night. Anyway, despite careful collimation, I certainly could not see Sirius B. There is no possibility with a telescope that gives such a messy diffraction pattern as this. But using a refractor of the same aperture, particularly a relatively long focal length one, would be a very different proposition, and I’d like to someone give this a go on a number of occasions from the UK.
I looked for the first time tonight for the pup from my observatory in Edgware, Outer London, Lat. 51N. I did not read the Observers’ Challenge and deliberately did no research in advance to tell me where it should be, in terms of PA, so as to get an unbiased result.
I looked for the Pup at culmination with a C-14 at 300x and 480x. I tried normal monocular observing, I tried using two eyepieces with a Denkmeier binoviewer, and I tried the addition of a dispersion corrector, set to correctly remove the spectral dispersion for the altitude. In all cases I could clearly see what I thought was the Pup, and I estimated its PA as 75 deg. by eye. It was easiest to see at the higher magnification, but once seen with that, could be seen at the lower magnification as well. It could be seen as well with one eyepiece as with two, but less well with the dispersion corrector: I imagine the the loss of light from the prisms in the corrector negated any benefit of concentrating the light better, but with the binoviewers, loss of light was countered by the benefits of binocular viewing.
My C-11 is always used for CCD imaging and has a Hyperstar system in place, so for visual purposes my next telescopes down in size are a 10″ Newtonian and a C-5, but they are on a mounting in a location from which Sirius is obstructed by a fence, so I could not try to see it with them.
I did try with my Celestron 100mm f9 ED doublet refractor that is mounted with my C-14. Using a magnification of 346x, having identified the Pup through the C-14, I intermittently thought perhaps I could see something at the correct PA, as an enhancement of the diffraction rings, but at other times I thought not, and I could not convince myself ultimately.
So my conclusion is that from London the Pup is very clearly visible with 356mm aperture, and would certainly be visible in a smaller telescope – maybe, at a guess, down to 200mm.
It’s now occurred to me that as I have my C-5 (127mm SCT) mounted on a dovetail, I can move it to the mounting I have the C-14 and 100ED on, so I could test the C-5 on the Pup in future. Past experience has been that the C-5 is less effective on doubles than the 100ED, because of more light in the diffraction rings due to the large central obstruction, so, despite giving a brighter image, it seems unlikely it would show the Pup.
I long ago decided as policy always to keep my C-11 in Hyperstar mode permanently, and the secondary resides unwanted in a drawer. It’s such a faff getting the Hyperstar alignments just right, as you say, it’s not worth going back to long FL imaging after prefecting it. Better to get another telescope – good 2nd hand C-8s go pretty cheap – and swap them on the one mount.
Thanks for the suggestion, Jack. I’ll take this issue to Council. I’m not sure it should be solved in the way you suggest; maybe relocating the event to a venue with bigger capacity, or holding another similar event elsewhere is the way to go. It certainly seems to be a victim of its own success.
Yes. The idea of carrying an f/11 4-inch refractor on an adequate German equatorial mount up and down stairs doesn’t seem like a realistic option to me.
I don’t recall ever looking through a Mewlon, but everybody says they are superb. However, there are advantages to the closed-tube cats, and I don’t think you should dismiss them out of hand. They stay clean inside, they don’t have spiders (either the animal or the optical kind) to affect the image, and the coatings do not corrode rapidly (this latter factor I find to be a huge issue in a polluted city for open-tube scopes). Dewing of the corrector is an issue, but can be greatly slowed with a dew shield, which can be a flexible piece of plastic. The ‘large central obstruction’ is a bit of an over-done preoccupation of some people, in my view. The great telescopes of the world (and in space) all have obstructions of 30-40% of the diameter, and no astronomer ever thought that made them bad telescopes. Contrast comes from many factors, including cleanness of the optics and darkness of the tube (baffling). SCTs tend to score well on these. The central obstruction throws a bit more light into the first diffraction ring, and if observing close double stars in fantastic seeing it is an effect you might possibly detect, but it doesn’t seem to damage planetary detail. I’ve been happy enough with Celestron SCTs to have owned 5 different ones.
My other thought on all this is that, to save weight to be carrying, you could consider: do you really need a German equatorial? As Peter says, they imply that annoying counterweight. There’s an increasing selection of altazimuth mounts, manual and driven, available now. Most of them, again, I haven’t tested, so how well they might do in your context I don’t know. But another correspondent of mine is currently having a lot of fun with a Skywatcher GTi altazimuth GOTO (but only with a 75mm short-tube refractor).
As far as the 2nd hand market goes, I’d recommend UK Astronomy Buy & Sell for bargains. I’ve bought loads of things off there over the years, and rarely had any problems.
Bresser is a German company that is associated with Chinese manufacturer Jinghua Optical Electronics Co. (who also now own Meade), so that probably gives where they are actually made.
One thing that’s not clear from your post, Bob, is whether you are looking to purchase a whole package: mount and telescope. If you are, we should be talking about the mount at least as much as the telescope. The mount of the Messier AR-102 looks too small for the telescope to me, judging by the picture on the tringastro site. If the telescope and mount are separate, for a manual mount, I recommend spending at least ⅓ the budget on the mount. For a GOTO mount, at least ½.
A separate 102mm f/11 OTA is sold by Altair Astro: their Starwave 102mm f/11. This looks different to the Bresser offering, and got a good review from Sky at Night magazine. I’d say a telescope of this size should not go on a smaller mount than the Skywatcher EQ5, or similar. Unfortunately, we may be getting to the point here that you would have difficulty getting this setup up and down stairs to your first floor flat, unless you disassembled it into several pieces each time.
A 150mm SCT or Maksutov would have similar image quality to a long 100mm refractor, but work with a lighter mounting, and the setup would be more stair-capable.
I agree with Peter’s comments. That graph he gives is very useful in judging what to expect with achromats. I would expect the chromatic aberration in the 127mm f9.5 to be quite intrusive, making it rather non-ideal for lunar and planetary work.
I haven’t tested these Bresser telescopes, but generally Bresser have a lower reputation than Skywatcher and Celestron – deserved or not – and much lower than Vixen (whose style they look to be imitating with their white paintwork).
I have some words to say on this subject in the December Journal, which will be out shortly!
Yep, this is the kind of thing that really needs a dummy run on an earlier night to get a feel for the difficulty of the problem. Glad so see some observers got something, if nowhere near 0.2s cadence.
This reminds me of the visit I recently made to Berlin, for the European Planetary Science congress. On the last day there was a visit to the longest refractor in the world, the Archenhold Telescope, which has a focal length of 21m and aperture 68cm (f/31). The longest eyepiece they have is 100mm, giving x210. This is the power they nearly always use. The telescope is in regular use for public observing, particularly by school groups. The eyepiece is the green bit in the photo.
The meeting has been organised in collaboration with Wessex Astronomical Society, and they chose the venue. We are dependent on the knowledge and contacts of local societies in organising such meetings, and the results are usually excellent, as I fully expect they will be in this case.
Indeed, but if importing yourself you’ll have more difficulty and expense if something is wrong with the product or it goes wrong later (which is common with solar scopes as they are delicate and precise things). This after-service is what you pay for by buying from a local dealer. As the US is a much bigger market, and most of these products are actually shipped from there, it is inevitable they will be more expensive here.
In the last year I have been showing Jupiter to the general public with a 100mm ED glass refractor with a magnification of 80-160, and when the GRS is on the disk, and it has been pointed out to them, 95% of them have been able to see it. This would be in the poor seeing we have been getting at the low altitude we have for Jupiter. So this gives a measure for people with no experience of looking though telescopes at all.For more experienced observers I have little doubt a 75mm refractor would be enough, under typical conditions, with a magnification of 80.I would say the GRS is easier to see now than it was in past decades. I think in the past a 100mm refractor or 150mm reflector would have been the absolute minimum, with good conditions.I do have 80mm and 66mm refactors as well, so now the question has been posed, I’ll see if I and others can see the spot with those this year.I covered many possibilities in my book “Setting-up a Small Observatory’, (Patrick Moore’s Practical Astronomy Library), still available from Springer, with descriptions and photos of methods of construction various people have used.
I used treated timber rails and guides and plastic rubber-tyred wheels, and, about 12 years on, this is the one part of my construction that has failed and needs replacing. The problem has been that wear by the wheels (even though there are lots of them, spreading the load widely) caused groove formation on the rails, which allowed water to stand, and the eventual decay of the rails. I build the shed in a modular fashion so it is not that difficult to replace the rails, as I anticipated this might be necessary. I can’t see any ultimate solution, other than using metal. Aluminium of the scale required however would be expensive, and steel is very heavy. I did try just surfacing the rails with aluminium, but that caused a different problem: water got capillarised in through the narrow gap. I intend to replace with new timber, but I may try varnishing with yacht varnish or something hard and hard-wearing, in an attempt to increase durability. But in the end none of these solutions last for ever, and 12 years is not too bad.
Anybody who studies or pursues astronomy in any dedicated way can call themselves an astronomer. I have met plenty of people who have ‘astronomer’ as their official job description who have not often, or ever, been in the circumstance described by Woolley. There is there a hint there of the kind of ‘macho suffering-cult’ that you often get in people’s definitions of their professions or hobbies in order to make them more exclusive: ‘You can’t call yourself an x unless you’ve done y extreme or uncomfortable thing’. Anyone with any sense rejects this stuff. There are a thousand ways to do amateur astronomy today, some of which involve extended physical contact with telescopes at night, but many of which don’t (solar observing, for example!), and in the BAA we value and encourage all of them.
Very sad news. I wonder how something good can be rescued from this.
I don’t think the BAA could commission something like the Yearbook, but we do already have our Handbook, and maybe that could be expanded, with the cooperation of some of the people who were contributing to the Yearbook, to include some of the most useful material from the Yearbook that it does not already cover. We could make the Handbook more pictorial and diagrammatic, market it more outside the Association, and charge an appropriate price to non-members. Maybe we could also pay something to contributors. However, that would require detailed consideration.
My method is to use tissues (one per wipe, then use other side, then throw away) plus de-ionised water, plus isopropyl alcohol. I alternate the alcohol washing stage and the water washing stage, going through a few cycles.
The main points I’d emphasise are being gentle, only doing a small arc each time, then lifting the tissue, and not rubbing in circles.
Also, don’t try to get it perfect. They’ll always be streaks. I do it maybe every couple of years, but my location is very dirty, with many diesel vehicles nearby.
Well it’s arguable that Council meetings are the equivalent of the meetings of a Board of a company. The minutes of these are not normally made available to shareholders, or members, of the company. I’m not saying I support this position, but it’s arguable.
David
To answer the other question, Council minutes are not available to members. I feel this is unsatisafctory, and I think they probably could be published, as could probably the minutes of the new, separate, Board of Trustees. This is just my personal opinion; there is nothing in the By-Laws to say they should or should not be available to members, but the tradition is that they are not, and that Council buiness is confidential.
David
