jambouk

I would highly recommend this book, can be purchased online for under £15 second hand, a newer edition exists but is more expensive since, it really does a wonderful job talking through the basics:

If going away from home where there is no mains power then you need batteries. Leisure batteries are best, but heavy. Work out how many watts everything needs per hour of use. Work out how many hours you want it to last for. Then I would double that number, and then ideally double that number again. That is the size of the battery you need. 
 

you need to work out how to make your connections more stable. Unreliable power supply is not acceptable. 

I’d get a second power lead, and cut the non-telescope end off, and attach the relevant connector(s) for the power unit you are using. Just get polarity correct else it will all blow up.

I suspect you’d get £75-£150 for the mount.

I wouldn’t bother with a wedge.

Try wide field with it with a DSLR. Else get rid. 

SCT you’d need to off-axis guide. Reflector will be long and unwieldy. I don’t have experience of the other two.

Have Mak-Newtonians gone out of fashion? 

Is this all inside an observatory or will be set up each night?

If it is just for imaging I would avoid adding further optical surfaces into the mix and not use a diagonal. 

Very nice. Seeing was stable.

I suspect it could. Just need to work out the balance. 

Yes, really nice. Do a custom white light balance with the fitler in situ to make the colours more natural and less blue.

James

JP-S, invariably these things are not just the result of one issue.

I think sorting out the flattener and its spacing would be a good place to start. I suspect if your PA is <1' then it is less likely to be field rotation.

James

Flat field and maybe some field rotation, how good if your polar alignment? 

Interesting. If there are no encoders, it must have some kind of marker on the gearing, but whatever, glad it is working.

I don’t know this set up but things which come to mind are:

Does it work with the handset (as in is there an issue with the phone software / communication side of things?)

Are the leads to the RA and Dec the correct way around?

Does it have any encoders? Can these be turned off to see if they are causing problems?

Where does it all get it’s time, date and location from? Are these correct?

Ignoring alignment, does it track, and slew as expected?

If you do a one star alignment what happens?

At the start of the video you said something about azimuth 360 degrees, but then said something about 61 degrees, what was that?

Good luck

It’s not the weight which is the issue it is the length and balancing and rigidity, and that is before you add a camera on to one end of the scope. 

Get it and give it a go, and if it doesn’t work, sell it on.

James

I recall being told some time ago that SCTs don't exhibit chromatic aberration as the last optical surface the light interacts with is a mirror before reaching the observer, which is why there is no chromatic aberration in SCTs. Thinking about this as I prepare a talk for my local astronomical society, this is rubbish, well bits of it anyway. Mirrors which are silvered on the light path side of glass have minimal (no) action in reflecting different wavelegths in different ways; I suspect traditional mirrors which are silvered on the other side of the glass and where light has to travel through the glass, get reflected and then have to travel through the glass again, may be different.

Anyway, this made me wonder [again] why there is no chromatic aberration in SCTs as the corrector plate is a single [simple] lens. 

Is this because the refractive index of the corrector plate is so low, that the amount of chromatic aberration is just so small it is not noticeable? Or is there something else?

Thanks for any replies.

James

Whatever order I place them all in, the lens are not tight, as though I've lost a spacing ring, which I don't think I have and which wouldn't have anywhere to go anyway. I got the eyepiece for £10, and have never used it and looking online it is dire anyway, so I'm going to pass it on to a friend who likes to tinker and see if he can re-arrange them and get it to work.

Thanks.

James

Yes I found that thread but not convinced any of them match what I've got...

James

Has anyone ever taken one of these apart and know how to put it back together... luckily everything fell out onto a towel.

James

I suspect the stock diagonal is basic so in terms of replacement I also suspect the proposed diagonal would reflect more light, but whether that results in a noticeable increase in brightness for you is an unknown - I suspect the view won’t look significantly brighter / clearer.

I suspect getting non-stock eyepieces would be more likely to improve brightness and clarity of views.

I also think that maybe you should think long term. Investing in a nice diagonal will be helpful if you subsequently get another refractor or a catadioptric. As such, if your existing scope will take 2” eyepieces, I’d think about getting a 2” diagonal. And if you are happy to wait a few weeks, I’m sure a nice one will come up on astrobuysellUK for about the same price or cheaper than the proposed 1.25” new version. Else put a wanted advert on ABS-UK.

James

P.s. keep the stock diagonal and eyepieces with the scope in case you ever want to sell it all - it would make it a more appealing purchase for someone.

Thanks Michael. The FR screws inside the Moonlite at the visual back side, but screws onto the focus tube which moves, so it preserves the distance between the FR and the camera; as you use the Moonlite the camera moves away from the telescope but so does the FR inside the Moonlite to the same proportion. 
 

I’d like to know if others have used the FR much further away from the visual back. Have you achieved this as you describe?

James

I’d contact FLO - they may not have one but will know what to do.

James

The standard Celestron 0.63x reducer screws inside the Moonlite Crayford focuser, near the visual back. But has anyone used the reducer the other side of the Crayford, away from the telescope, but still still preserving the 105-110mm spacing to the sensor?

Reason being is to be able to switch between visual and imaging without having to remove the Crayford.

Thanks

James

Page 37:

Does anyone have any CAD software which can open *.CAD files, which I think originated in CADRA software or maybe QUICKCAD though I can’t find either to download to try. The files won’t open in AutoDesk or any of the other packages I can find online. I’ve attached a sample file here. Thanks for any replies.

James

NAS240000A.1(v01.02).CAD

Thank you.

The 12v would be from a 12v battery bank, charged by solar / wind. So clearly I need to do some calcualtions to see how much power that is going to draw.

The camera(s) would need to be weather proof.

Food for thought, thanks.

James