Cosmic Geoff

I have posted intermittently in the EVAA Observations sub-section and Planetary thread.

This is a misconception. A Dob mounted scope can be any size you want, from a table-mounted mini dob, to one so big you need a tall ladder to reach the eyepiece. If you want GoTo, that's fair enough, as it is a personal choice whther you want to let the hardware find objects for you - especially useful if like most of us you live under light-polluted skies, or prefer to find things by the traditional methods. But if your budget is £600, that guarantees that the scope and GoTo mount are going to be relatively small and portable. If buying new, there are plenty of GoTo outfits in this price range. Just be aware that whatever you buy will be a beginner outfit rather than a "Telescope for life" and once you have figured out how to use the scope and the mount, and discovered in what direction you want to take your new hobby, you will probably be looking to buy some different kit. I won't try to recommend a particular outfit - so long as you buy one of the major brands and from a specialist astronomy dealer, it matters more that you buy something and get started. You can save money by buying used, but for the novice this carries the risk of buying a 'dog' because of knowing too little about telescopes. Forum sponsor FLO has a range of beginner telescopes.

Speaking as a former technician, I don't think computers are that delicate. It should be okay so long as its cooling systems work. The internal components should withstand at least 70 deg C (I58 deg F). On the other hand, keeping the observatory and telescopes cool would definitely be a good idea, in order to help it cool to ambient at night.

A dismal situation all round. Unfortunately the majority of Brits live in urban centres, meaning that the majority of Brit amateur astronomers live under light polluted skies. My bete noir is a supermarket unloading bay with a light that comes on automatically every time a car drives past, and a neighbour who can't afford curtains... As a compensation, I have found that EEVA vastly improves the visibility of faint fuzzy objects. Dark skies would be great, but getting to them is logistically difficult.

While these guidescopes will also work as an optical finder, they are intended to have a camera directly connected, and a diagonal will excessively extend the path length. If you really want a RACI finder that takes 1.25" eyepieces, you may have to buy again. And note that to make the Svbony work properly as a finder, you will need an eyepiece with crosshairs.

I totally agree.

I have three setups, each with a replacement value of over £1000, and would have trouble deciding which to take to that desert island. Largely a choice between imaging and visual. And does the island have power for recharging power tanks and laptops?🙂 If it's a 'luxury' purchase, why not go for a nice sexy ED or APO refractor?

If you've bought an ASI533MC Pro, then I recommend a GoTo mount, e.g a EQ5 Synscan. They have better motors plus the GoTo will save you time and you can plate-solve & re-sync (on some fields at least) to confirm your target area. Your next step will be to decide whether to image unguided, or upgrade to guiding with a guidescope and guide camera or an off-axis guider. Who said imaging was cheap or easy? You may also want a focal reducer for faster imaging. I got a f6.3 reducer for my C8 but I don't know if the same one works on a C6. They cost about £150.

Any mount would be better than a 6SE on a wedge. I assume this is for imaging. I have seen posts from users who found that using a wedge did not meet their expectations. An EQ5 Synscan would be far more suitable. Not the easiest mount to use compared with an alt-azimuth Nexstar, but it works.

Perhaps you are just expecting too much. I have been using Celestron Nexstar mounts for years and have found that the sought object generally lands somewhere in the field of a 25mm eyepiece. It's rare for it to land in the exact centre of field, or in the field of an 8mm eyepiece. With a Starsense + AVX, I doubt that the GoTo accuracy relies on an accurate polar alignment. My alt-az Starsense works with no polar alignment at all. If you are imaging there are other things you can do to refine the aim, e.g plate-solve & resync.

I am not aware of any significant differences. The C8 OTA has an assortment of holes in the end castings allowing it to be attached to a single fork, twin fork or EQ, and the tubes are given different colours, and some have a rear handle and some not, but the optics are all the same. In some cases the price of a C6 bundle is discounted to the price of the OTA, making an interesting buying choice...

As a former mechanical engineer I find it unlikely that the vane could have been bent by rough handling in transit without collateral damage to the tube and packaging. An extremely high acceleration would be required to bend a vane. It wasn't dropped from an Amazon drone, was it? 🙂 If you would prefer to tackle it yourself rather than pursuing the guilty party, note that what is bent can usually be un-bent.

Celestron don''t offer many Newtonians nowadays. They do offer a 130mm Astro-fi Newtonian for an affordable £399. There is also FLO's own Stellalyra brand which seems well received. I feel though that if you are buying to get a first scope rather than for some specific purpose it doesn't matter hugely which of these leading brands you go for. Some of the parts may come from the same Chinese factories.

The 130PDS is intended for imaging, though it by all accounts will also work well for visual. If you buy the cheaper version of the 130 intended for visual use, it has a different focuser and will not come to focus with some cameras. It depends on what you want... I formerly had a Newtonian with a single-speed focuser. It was a bit tricky to focus, but I managed to find a helical focuser for around £20 that would fit. A dual-speed focuser conversion would have cost far more.

For visual use, polar alignment is not at all critical. If you attain a usable polar alignment (by whatever method), then you could mark out the ground so that next time you set up the mount you just have to place the tripod legs in pre-marked positions. If you are aligning for imaging, there are various methods you can use that don't require Polaris to be visible.

It seems curiously cheap considering that an EQ3-2 mount costs £209 and a 150mm Newtonian around £200 elsewhere. It's not a major brand AFAIK and though it might turn out to be some sort of clearance item it could turn out to be a risky buy for a beginner. Paul, I assume that you are not prepared to buy some little starter scope with your credit card and repay with your lump sum later?

Why wait till August? I can't help thinking that your time and energy over the next few months would be better spent in looking through some small telescope rather than peering at screens agonising over what to buy. The perfect all-rounder telescope does not exist.

I have a similar package with the 127mm Celestron SLT Mak. Basically the same mount and OTA but with the Celestron brand and the Nexstar software, which IMHO is more user friendly than the Synscan. The OTA is great but the mount & tripod are a bit cut price - but very portable. The tripod is too wobbly for anything but visual use, though I have done some imaging with the mount custom fitted to a wood tripod. Overall it's a fine introduction to GoTo visual astronomy. The Celestron SLT is currently £599, a d*** sight more than I paid for mine. There is an Astro-fi version at £499 (no handset).

Here is an image of the M97 Owl Nebula. Taken with 102mm f5 achro, ASI224MC camera, live stacked, 10 frames x 30 sec, processed in GIMP. Bortle 6 skies.

I have the 127mm Celestron Mak SLT - a variant of some of the outfits you have been considering. The 127 Mak is at the upper limit of what this mount will handle, and with the tripod supplied is only fit for visual use. The SLT mount does a bit better when custom fitted to a home-made wood tripod. Contrary to what some people claim, the capabilities of entry level mounts with a max capacity of 5Kg will be limiting. I now use a EQ5 Synscan for some of my attempts at imaging. It is neither cheap nor particularly easy to use, but does deliver a good stable imaging platform. The EQ5, like the AZ4-2, has a 1.75" stainless steel tube tripod - a good solid tripod and like scaffolding compared with all the lighter weight tripods that come with the entry level kits. Similar tripods can usually be bought separately. I have used both the Celestron Nexstar software (in allt-az form) and the Skywatcher Synscan (in EQ form) and find the Nexstar much more user-friendly.

Here is an image of NGC3242, taken with my CPC800 and f6.3 focal reducer, processed in GIMP. Camera is ASI224MC. The sky was hazy.

A lot of CMOS astro cameras are sensitive to infrared. Check out the specs of the ZWO ASI224MC, for instance. I have used mine to image planets in near infrared, with an IR-pass filter. All DSLR cameras have an IR-cut filter, which some astro users are keen to remove...

Just for clarity, the optical tube assembly is a "C8". The "8SE" or "C8 SE") is the whole outfit including the 6/8SE mount which is essentially a portable visual mount. In answer to your question, the suitability of the C8 for imaging depends on what you hope to achieve. I found that mine is good for planetary imaging, but (in the form of a CPC800) was not much good for imaging smal fuzzies until I got the Celestron f6.3 focal reducer, which has transformed it and it now takes nice images of planetary nebulae. Since you already have the C8 OTA and th CGEMII, I suggest you buy the focal reducer (often available used) and give it a go. It will give larger scale images than the Stellamira 90mm.

Yes, as the name implies, focal reducers reduce the effective focal length (just as a Barlow lens effectively increases it). I have not come across any focal reducers sold for use on Maksutovs. They are frequently used with SCTs ( and I can personally attest that they make a huge difference if you want to image certain objects with a SCT). Focal reducers are also used with the varieties of refractor used for imaging. The reducer will not degrade the image, and indeed may actually improve it if combined with some other function. Note that focal reducers are not cheap. (Some of them cost more than your entire £500 budget). The alternative, of course, is to buy a scope with a faster focal ratio in the first place. Such as (in the budget range) a f5 Newtonian, or one of the Skywatcher Startravel short-focus achromats.

Paul- if you are ping-ponging between various designs of 'scope and mount, I would suggest you take a systematic approach to narrow down the choices: Portability - how far do you have to carry it? Weight (you can look up the spec) Assembly time - this can vary vastly, from carry it outside and start using it, to over half an hour with a complex setup. Visual or imaging? If you have a clear idea that's good. For visual, you can avoid equatorial mounts unless you particularly want a manual mount that rotates about one axis, or tracks with an electric motor. An alt-azimuth GoTo will track on both axes. GoTo or manual? GoTo can save you a lot of observing time, once setup, but some people prefer the old-fashioned approach. Manual or equatorial GoTo? For visual the alt-az GoTo is much less bother to set up, and you can also image with it - you'd be surprised what is possible. You only need an equatorial GoTo for the more challenging long-exposure imaging. Dobsonian design - vey popular because of low cost and simplicity - but GoTo versions are no longer cheap, and none of the Dobs are well suited for any sort of imaging. Focal ratio - be aware that different telescope designs have different focal ratios, which have a bearing on what they are best suited for. That said, it does not matter hugely what you get, so long as it is usable and of decent quality. Once you have had a go with it you will have some valuable experience and can buy something else if you feel the need.