Cosmic Geoff

It is not essential to find the instruction manual or identify the precise model. As others have pointed out, this is a Dobsonian mounted Newtonian telescope - a relatively low-tech device, and when fitted out with standard eyepieces and a standard optical finder can be used in a standard way.  

Of course, if any bits are missing you may need our advice for sourcing replacements.

You do not explain what you are trying to image with this camera, or with what telescope. Here is a helpful review:

SVBONY SV105 Review (Is It Any Good?) (telescopeguides.com)

It is a common feature of such cameras that the effective field of view is very small even if you select in the capture software to use the full chip. This camera is intended for planetary imaging, where the full area of the chip is not required, except for the Moon. 

There is nothing you can do to 'zoom out' other than use an optical 'focal reducer' (q.v.)

You do not have to use the AstroDMx software. The review recommends Sharpcap.

I had that problem a while ago and after some investigation (different cameras, etc) figured out the cause, which IIRC  was that in Sharpcap's right-hand panel, I had set 'Debayer preview' to one of the four-letter options instead of 'On'.

There is nothing on Google about this telescope. If you want an answer, post some pictures of the telescope and its mount.

The recommended f-ratio for planetary imaging with a scope depends on the pixel size in the camera.  This is often overlooked.  With a pixel size of 2.9um (as in the ASI462MC, for instance), this will match a f10 SCT, depending on whose advice you are following.

The ASI290mm and the ASI462mm are quite similar except for some details of the performance.

In practice I found that the ASI462 worked well with my f10 203mm SCT without a Barlow lens and adding a Barlow conferred no benefit.  New and more advanced cameras are introduced frequently. (The ASI462MC is already discontinued.)

Opinions may vary, but I think this is a combination to be avoided. I had an 8" Newtonian on a manual EQ5 for a while.  I already had a smaller scope on a GoTo mount, and I found the 8" Newt/EQ5 to be almost unusable.  It worked well when I could find anything with it, which proved remarkably difficult.  The eyepiece got into awkward positions, including potentially over seven feet off the ground with the tripod fully extended.  I soon disposed of the tube, and bought an 8" SCT on a GoTo mount, where the eyepiece remained in a convenient position, and I could find things...

I kept the mount and later upgraded it to a Synscan GoTo.

I don't think the "buy once" theory works in practice, as one's astro interests develop and change. 

Alas, NGC1360 is too low to be accessed from my back garden, and is now at its greatest altitude in twilight.

2 hours ago, Wolfstar said:

In terms of a permanent base EAA setup i would probably look towards a Comet Hunter or 8"SCT with reducer (any fast, large aperture and low maintenance). 

I actually have an 8"SCT with focal reducer, but I only use it occasionally in the EEVA role, for EEVA of small objects. And it has an alt-az mount. Surprisingly enough you can use an alt-az mount for EEVA, as the live-stacking largely takes care of the field rotation.

If you have a recent model Synscan handset, you can plug a USB cable into it and control the mount that way for plate-solving etc.

I suggest that you as far as possible put together a EAA rig with what you have to hand, and see how that goes.  You however appear to lack a widefield scope, which could prove an expensive acquisition.

My current preferred arrangement is: 102mm f5 achromat,  ASI224MC, helical non-rotating focuser, EQ-5 Synscan mount, Sharpcap 4.  (essentially stuff I had already)

A total integration time of 30 mins seems ambitious, unless you go somewhere really dark.  I usually do 150 secs or so from an urban area.

I don't think that modular construction, or new drives for old mounts, is ever going to be cheap. But it occurs to me that with the advances in technology available today the fitting of new drives to old mounts could be facilitated by using laser-scanning to design brackets and couplings and then printing them so that a new modular drive can be attached.  (If this sounds like science fiction, I should point out that this is how up-to-date private dentists produce tooth crowns in one visit - search for CEREC.)

I note than none of the 'alternative' GoTo drives for the EQ-5 seem to include a full GoTo handset - worth around £140 these days - relying instead on a computer connection.

Sharpcap works well for image acquisition, and the successive versions have become increasingly sophisticated, offering polar alignment, focus aids, etc.  It allows you to 'live stack' of you are interested in EAA.  (Rival capture programs are available).

I checked out APT but found it complicated and never put it to real use.

My advice is to try Sharpcap, and if you feel you are outgrowing what it has to offer, try NINA or APT.  Whether you intend to use an astro camera or a DSLR also has a bearing on which software you will want to use.

2 hours ago, tezz said:

Because Celestron was selling it cheaper.

And if celestron can sell it at that price.

Then should be able to sell it to shops cheaper.

Amazon have the buying power to lean on suppliers for a lower wholesale price. They allegedly underpay and overwork their workers and pay little British business tax.  If you have a problem, do you think Amazon will deal with it effectively?  And do you think they will continue to sell astro kit at those low prices once they have put FLO, Tring Astro, etc out of business?

3 hours ago, tezz said:

@Cosmic Geoff I just looked and my evolution comes with a celestron Star Diagonal -1 1/4

Looks like I don't need to buy one?

You don't need to buy one.  Few people are bothered by the L-R reversal.

4 hours ago, tezz said:

So is my link the right one.

It's the cheapest I've found 

It looks like the correct one for your scope, but why not support a proper astronomy dealer who needs your money much more than Jeff Bezos does?

4 hours ago, tezz said:

Is this it?

https://www.amazon.co.uk/Celestron-Field-Lens-Corrector-Reducer/dp/B00009XVHZ/ref=asc_df_B00009XVHZ/?tag=googshopuk-21&linkCode=df0&hvadid=309904628344&hvpos=&hvnetw=g&hvrand=3482787380875555236&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1006524&hvtargid=pla-404336624377&psc=1&th=1&psc=1

Looks like it, but why not buy via a proper astronomy site rather than via Amazon?

A scope of 50 to 80mm aperture will not perform well for planetary imaging.  For that you need something like an 8" SCT (on your mount.)  AFAIK any of the telescopes you list should work fine with an astro camera.

Back focus is irrelevant if you are imaging planets (or other small objects) or live-viewing them on a screen.  It becomes an issue if you are using a large-chip camera and want the image to be sharp right to the corners.  As it happens, the standard Celestron diagonal is about the right length to give the correct amount of back focus (it does not have to be accurate to .001 inch).   Yes, it will reverse the image L-R but you can undo that in software.   There are all sorts of other ways of providing some extension. For instance, if you buy a SCT to T-thread adaptor, you can then use T-adapter tubes to connect the adapter to your camera, which should have a T-thread on its front end. SVbony  do a kit of T-extension tubes which you can play with to get various extensions.

If you have not done so already, consider buying the Celestron f6.3 focal reducer, which will do a number of useful things for you: convert your scope to a f6.3 (faster for imaging and live-viewing), give a wider actual field of view, and IIRC provide some field flattening.

Note that I was obliged to use a diagonal along with my f6.3 reducer, otherwise the imaging train hit the base of the mount when trying to aim at high objects!

14 hours ago, stafford_stargazer said:

Thanks I'll check that out, what would you call a good Barlow?

Any makes or links pls?

Bear in mind that the C6 has a f10 focal ratio, which renders a Barlow less than necessary for visual use and also of doubtful use for planetary imaging.  If you use a camera with a pixel size of 2.9 um rather than the 3.75um of the ASI224MC, the scope will deliver an adequate image scale without a Barlow.  

In practice I rarely used a Barlow for planetary imaging with a C8 as I found it delivered little or no benefit and made the outfit harder to use.

I got the Sharpcap 4.1  comet tracking feature to work tonight (9th Feb). I don't know what I did that I didn't try before, other than waiting for an exposure to complete giving the display time to update.

The second telescope is best used for widefield viewing, not looking at planets. The aperture is rather small for viewing galaxies and other 'faint fuzzy objects'.

With a budget of $185 you are in danger of getting a telescope that is disappointing and discourages you from pursuing astronomy further.

I bought  a license and tried again last night (6th) but could not get the comet-tracking feature to work before cloud rolled in.

On 04/02/2023 at 11:01, PeterC65 said:

The next version of SharpCap, v4.1 which is available as a beta release, has a feature for tracking comets so that the stars become lines instead of the comet. I've downloaded it and it seems to work fine alongside my existing v4.0.

I downloaded the SharpCap 4.1 beta and tried it out last night on three comets.  To my disappointment, I could not try the comet-tracking feature as it insisted a Pro license was required, despite some text indicating that one could try out NEW Pro features without a license.  I suppose I ought to buy one just to support the software creators.

4.1 also made a pig's ear of saving the comet image files in the right folders.

Yes, it is a beta, but I will stick with 4.0

After accidentally unscrewing the wrong bit of my ASI224MC in the dark, I found that exposing the sensor is a bad idea. It is quite difficult to get rid of spots and smears that show up subsequently when imaging, and difficult to determine whether they are on the sensor or on the clear window. 

It is possible to clean the window disc by the usual methods. As for the sensor, it seems safe to dust it off with a fine-bristled art brush. Be careful of blowing on it, as a aerosol may deposit unwanted stuff. Vacuuming might work. IIRC there are materials and techniques for cleaning DSLR sensors. 

Replacement window discs may be available from ZWO.

1 hour ago, Shimrod said:

The comment on orientation remains valid though as placement of the observatory will block out one quarter of the sky. Might still want to consider keeping one of those visible directions north in case of a mount upgrade in the future.

Apparently the observatory section has low sides but a fixed gable end. I would be inclined to make a modification there, and make the top half of the gable end hinge down.  Nevertheless it is an improvement on the high-sided roll-off-roof designs I have seen pictured elsewhere.

44 minutes ago, Seoras said:

There seems to be an awful lot of play in the alt axis; I got in touch with Celestron support and they suggested it might be fixed with the backlash settings but I’ve had no luck so far. There is probably about 4-6mm of “loose” movement and the scope will slip downwards at the slightest touch. When trying to adjust the backlash settings I could hear the motor engage to compensate for backlash but it still leaves the looseness. I looked online and found a video that shows how to tighten the clutch with a big nut on the mount but mine is already tight.

I have the same experience with mine.  I could not adjust out the vertical backlash with the settings, and the scope once slipped downwards while in use. I tightened a large nut but it was not very slack anyway.  The 'slipping downwards' has not recurred.

Your videos show a lot of play, but I do not recognise that part so cannot comment. 

My advice is to just live with it unless it is making the outfit unusable for visual use.