Cosmic Geoff

I think you are about to find that the words 'budget' and 'astrophotography' do not belong in the same sentence. I am not sure what you mean by 'astrophotography lens'. If you get a regular photographic lens (fixed or zoom) with a moderate focal length (e.g. 70mm or more) and attach it to your camera, you can make a start. Such lenses are not 'cheap' especially if you are buying new, but there are plenty of used ones on ebay. Thus equipped, you can try imaging star trails, or invest in a star-tracking mount and try making some wide-field astro images. A later step is to use an astro telescope as the lens. Which generally requires the use of an expensive mount. I expect someone with more experience in the field will be along soon to comment.

I managed to find out what this is. I have to say I have never seen anything good written about Newtonians of such a small aperture. All one can say is that it must be very cheap to manufacture. I wonder how big the central obstruction is in comparison to the overall aperture. 76mm aperture is quite small. A refractor of this size would be preferable, or a larger table-top Dobsonian in which your money is spent on the optics and not on the mount.

We won't be familiar with the brands you cite, or their quality. We are familiar with brands like Celestron and Skywatcher. You should be aware that low-priced telescopes may be of poor quality. As for which of the models you cite to choose, be aware that the longer focal length ones should perform better on planets, but the maximum field of view will be set by the lowest power eyepiece in the kit (20mm) giving a field of view of a degree or so. That's enough to give a view of many star clusters etc. The 70x400 mm scope will give a much wider field at low power, but in practice may not give a good quality image at high power, regardless of what lenses you use on it. If you have the option of buying a table-top Dobsonian of 130mm aperture (or more) you should consider that option. If these are not available to you, the longer focal length refractor might be the best option as a general purpose starter scope. If you have access to a computer, you can download the free program 'Stellarium' which has a field of view add-on where you can enter the details of various telescopes and get an idea of what will apear in the eyepiece. The vast majority of deep-space objects are very small - it's just a few brighter ones popular with amateur obeervers that have a large angular size.

I have a CPC and there is no way I would risk using it with an improvised PSU. I spent £40 just to replace the battery in the power tank I normally use. I wouldn't risk using a computer PSU on an expensive Skywatcher mount either.

You might get away with it, but I worked with specifying instrument power supplies in my last job, and discovered that in most of these supplies, the 5 volt line is directly regulated and the other outputs just follow it, so that the +12v output is ill-defined if it is the only output loaded. Considering that proper mains PSUs for a mount are inexpensive and better protected against water ingress, I would not risk it. Likewise if you require more power to run sundry accessories like dew heaters, you can buy a PSU properly boxed up with terminals and output meters.

The views ought to be clear with any camera. The video actually mentions two cameras, and newer models are announced all the time. I actually re-purposed a planetary camera, but it's up to you which model you go for. More pixels and a physically large chip are (I assume) an advantage for EVAA, particularly if you want to capture large subjects.

I would suggest you start with whatever kit you have to hand, see how you get on and take it from there. I started with a 102mm f5 achro scope mounted on a Celestron SLT mount, with ASI224MC camera and Sharpcap on a laptop for capture & live stacking. I now have the 102mm achro on an EQ-5 Synscan, ASI224MC camera, with Sharpcap 4 on a newer laptop, with the ability to platesolce & resync. Processing with PIPP and GIMP later improves the look of the saved images. Also available: a CPC800 with f6.3 focal reducer if I want to try for more resolution.

A Celestron C8 SE would give you more aperture +GoTo in a portable package. The GoTo would save a lot of time spent standing around and aiming the scope. Not cheap though with the recent price increases, unless you buy used (and there are lots of them around.) I have used mine for galaxy viewing in dark Devon to great effect. One has to say though that 'faint fuzzy objects' are only well seen from a really dark site. One can see a lot more detail by imaging and EVAA, even with a small scope.

I think there is very little demand for larger manual alt-azimuth mounts other than Dobsonian for newtonian reflectors because the scary price tag soon sends prospective buyers running in the direction of a Dob with its economy chipboard mount. If you want to spend your money, I saw a nice series of alt-az mounts at an astronomy show, which had digital setting circles or GoTo as an optional extra. The Rowan AZ-100 takes plenty of weight on each side for a mere £1049. (tripod and accessories extra) In the smaller mount sizes there seem to be a number of alt-az offerings from SkyTee etc. As for tripods, the 2" gauge tripods used with the Skywatcher EQ-6 mounts should be adequate.

I'd never have thought of that. But the adapter is threaded all the way through, and there is a recess at the inner end. OTOH it is much easier to swap between filters, e.g. visual and IR pass, if they are screwed on the outer end.

Actually, I do not think that balance is important with a powered alt-azimuth mount. I have my C8 pushed as far forward in the clamp as it will go, to minimise the potential for bulky accessories to hit the mount when aiming near the zenith. The worst that can happen is that the azimuth clutch will slip and ruin the GoTo alignment. (You can test the resistance of the clutch, if you dare, by pushing down on the OTA tube end.) The Evolution has a high-quality gear train so there should be no need to worry about overloading it. I recall reading an discussion on the US Cloudynghts forums about Celestron alt-azimuth GoTo mounts being loaded with heavy cameras and other accessories - and no problems reported.

Not with a SE mount which has an altitude slip clutch. I would not even think of lifting the assembly by gripping the OTA. "A C8 OTA isn't that heavy, the handle at the back " The current C8 Evolution and SE OTAs do not have a handle at the back.

Fine, so now we know it's a SCT on a relatively portable mount. I have the C8 SE alt-azimuth GoTo, and yours should be capable of being handled in the same way. If you had only level surfaces to contend with, you could pick up the whole thing and carry it outdoors through a standard doorway. What I do if I have to tale the C8 SE to an awkward part of the garden is as follows; Detach the mount & OTA assembly from the tripod, and carry the mount/OTA outside and set it down on some convenient surface (it should stand up safely). Pick up the tripod and carry it outside and set it up in the final position, with legs extended as required. Check the tripod top is level. Collect the mount/OTA and reattach it to the tripod. When done for the night, I fit the relevant OTA and eyepiece covers and reverse the procedure, leaving the outfit set up indoors to dry off. In several years, this has never caused any problems. Note that in the case of the C8 SE, Celestron's notes indicate that they don't expect you to separate the OTA and mount. I recommend that you treat the C8 Evolution the same way, as the C8 SE mount /OTA forms a manageable lump, and separating them is quite awkward in the absence of handles. If you must separate the OTA and mount, which I really do not recommend, invest in an accessory bar to fit on the free side of the OTA to act as a grab handle. IIRC, ADM do one for about £70, which is cheaper than a new OTA should you fumble it. BTW, do you have a dew shield? It is a non-optional accessory which SCT marketers don't like to show you in the publicity pictures.🙂 EDIT: Just remembered that when I took the C8 SE to Devon a few years back I carried the complete assemblage down & up a flight of 3 or 4 steps several times (watching my footing) rather than go to the bother of splitting it. I don't know if I would want to do that regularly.

I cannot comment unless you make it clear which Celestron 8 you have. There are quite a number of possibilities.

With a C8, I found that a star looks like a badminton shuttle if the collimation is really bad.

The ASI224 body connects to a T or T2 thread. I have some of these adapters and they fit - sorry I can't be more specific. It also screws into a flip mirror diagonal I own. You should be able to find something that gives a 1.25 nosepiece, but note you do not have to connect the camera that way. It also has a 2" diameter section, BTW.

Imaged with 102mm f5 achro, ASI224MC, EQ5 Synscan on 14 July around 22.30 UT. Captured with Sharpcap, processed in GIMP. Urban sky and moonlight.

Some images of the planets taken with CPC800, ASI224MC, ADC, ZWO filters, captured in Sharpcap 4, processed in Registax6 and Photoshop Elements. There was some thin cloud about. Because of it, I could not get a satisfactory infrared image of Saturn at all. The Mars images were taken in visual and infrared, with and without x2 Barlow. The dark area checks out as Mare Sirenum. Angular diameter of Mars 7.7" The planets are quite widely spaced, with Saturn already in South by the time I set up, so I dealt with them in order of title.

I wouldn't worry about pinholes and scratches on the full-aperture filter. With a 127mm scope, a pinhole 0.127mm in diameter would let through one millionth of the unfiltered light. I did however have an accident with my home-made solar filter, where the pistoning effect of putting it on and taking it off displaced the inadequately secured film so that some unfiltered light got around the edge of the film. It made a nasty glare, but fortunately I realised something was wrong before my eyesight suffered any damage. To repeat what others have said, the Herschel wedge does require a supplementary filter. The Herschel wedge system, unlike the full-aperture filter, has the potential for overheating parts of the telescope, as noted. The projection method is probably safest of all for one's eyesight, but has the potential for overheating parts of the telescope, especially eyepieces with plastic parts, e.g. the basic eyepieces supplied with many Skywatcher and Celestron kits. Bits melt. I also have an eyepiece cap with a hole melted in it.

I have an 'older' Canon camera - a 300D, which I acquired from another astronomer to see how I got on with a DSLR. I found that (with a zoom lens purchased separately) it still works well as a daytime camera BUT at night I could not see any of the controls, the screen on the back is fixed, tiny and does not give a 'live view', the support software to facilitate downloading images only works under Windows XP. And it is not supported by the astronomy program APT. It was possible to get the images out using a card-to USB adapter, or, oddly, using Mint Linux. I have not seriously tried using the 300D for astro imaging. It seems like too much bother. Before buying any older camera, I advise you checking carefully to see you don't run into the same problems that I did.

Alas, astronomy is not a cheap hobby. Both the scopes you cite look like models to be avoided at all costs. If your budget is severely restricted, I suggest you look at the type of scope known as a 'Dobsonian' or 'table-top Dobsonian' which should give you a fairly decent scope on a very basic chip-board mount. Most of your dollars will hence go into the optics, and if you decide you don't like the mount, you have the option of saving up for a better mount and putting the tube on it. Some budget Newtonian or Dobsonian-mounted scopes now have fixed collimation of the primary mirror, which takes that issue out of your hands.

I tried an ASI120MC against a ASI224MC as a trouble-shooting excercise recently, and concluded (among other things) that while the ASI120MC worked well enough as a planetary camera (its intended role) it is too noisy to be very useful for long exposure deep space imaging. Yes, the field with these planetary cameras is small, but it might conceal optical aberrations in some scopes that would be more obvious with a larger sensor chip.

Since you have a Celestron scope, I suggest you read the above and take a good look at the diagonal that came with your scope, before throwing your money about. If you can find an extension tube, you can test the scope straight-thru without a diagonal. My Celestron C8 came with an excellently performing prism diagonal. (#93653-A)

That particular telescope is intended for wide fields and does not do well at high magnification. With low power/wide field the manual equatorial mount is less useful and an alt-azimuth mount would be easier to use. Some beginners find the equatorial mounts a pain to set up, and they are not particularly useful unless motorised or in full GoTo form (highly desirable for imaging). I could not navigate the Norwegian website but (if available) you might look at a longer focal length version of the 102mm, or a table-top Dobsonian of 130mm or 150mm aperture. Or a ground-standing 150mm Dobsonian.

Some of your wants are contradictory. "Extensive lunar study" does not seem compatible with having to continually nudge an manual alt-azimuth mount. "Lunar/planetary digital photography" requires at least a driven mount (meaning equatorial), or alternatively an alt-azimuth or equatorial GoTo. You could try managing without, but you will probably find that it is no fun.