Good 80mm refractor or CCD?

[earth titan]

Well I've pretty much decided my permanent set up will include a C9.25 and a good quality refractor.

I'm currently delighted with my FPL53 80mm refractor but long term will be looking to replace with a good un but I'm also torn between persevering with my DSLR or going over to CCD.

So what would be best? A better scope or a move to CCD and filters? It will be dedicated to AP - looking at spending around £1500 (next year).

Typed by me on my fone, using fumms... Excuse eny speling errurs.

[pete_l]

It's a tricky one - though I'd go for the CCD.

A nice mono CCD will set you back all of your 2013 budget on its own.

The filter wheel will be another £300-ish and a set of LRGB filters (get the parfocal ones) will be another £200.

The bad news is that, if you're like me, you'll want a set of narrow band filters as well. A set of Ha, Sii and O3 filters will be another £300 - so that looks like the 2014 budget is spoken for, too.

[sologuitarist61]

I am in a similar situation Tom. My DSLR does OK but I can't help feeling I would be better off with a CCD. However, I tend to agree with Pete (above), you may find your quality will go up in leaps and bounds with the scopes you already have but with n astro camera.

[Earl]

Getting a better 80mm is going to be subjective at best unless you dig deep.

A CCD will give you a better step up for you money imo. The Mono vs OSC debate is of course the next step to consider.

(Edit)

A mono ccd setup might push your focuser you might need to consider a new focuser if you plan to do this. OSC on the other hand will be more or less like your DSLR weight wise.

[ollypenrice]

To me it's an easy question to answer. CCD. An ED80 with flattener/reducer and good CCD will greatly out perform a Takahashi FSQ and DSLR. DSLRs give big chips at low cost and that's about it. Now I know someone will link to a CCD-like DSLR image but I'll give ten to one that it will be an image from a very fast astrograph at a very fast price - and if so it should have had a CCD in it!

Add to that the fact that the C9.25 is very slow and has a limited image circle, so a CCD would be faster and probably have a smaller chip residing in the clean part of the circle. A double whammy in favour of CCD.

Olly

[laser_jock99]

Get a CCD with an DSLR sized chip - 2015/16 budget gone as well!!

[earth titan]

As I thought. More expense :-)

CCD is looking good. Probably mono with filter wheel so I can do narrowband as well.

Rather than all the expense at once, I wonder if filterwheel with DSLR for a bit of narrowband makes sense then CCD later on.

What would be the benefits of a filterwheel and a DSLR? I'm presuming RGB is pointless but would luminance /narrowband improve images?

Typed by me on my fone, using fumms... Excuse eny speling errurs.

[kirkster501]

You have to draw a line somewhere mate. Only so much you can do as an amateur without blowing the household budget and your list of desirable equipment can be never ending ! I follow Steve Richards advice in his book about being realistic what you can afford and enjoy what you buy; not his exact words but that's his sentiment.

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[pete_l]

Rather than all the expense at once, I wonder if filterwheel with DSLR for a bit of narrowband makes sense then CCD later on.

I'm afraid it doesn't work like that.

Apart from the physical difficulties of gluing a FW to the sharp end of your DSLR, it's unlikely that the 1¼ inch filters (much, much cheaper that 2 inch filters and good enough for most "small" CCDs) will cause a lot of vignetting of your images - the DSLR sensor is simply too big for them.

Also, narrow band filters let through very little light - hardly any (though what they do let through is much less affected by light pollution). That means that you'll need to take longer sub-exposures. If you try doing that with your DSLR, the noise from its uncooled sensor will result in poor images. The DSLR will also only "see" NB light on 1 or 2 pixels of its RGB Bayer matrix - whether it would be able to create a passable image from that is questionable.

[earth titan]

I'm afraid it doesn't work like that.

Apart from the physical difficulties of gluing a FW to the sharp end of your DSLR, it's unlikely that the 1¼ inch filters (much, much cheaper that 2 inch filters and good enough for most "small" CCDs) will cause a lot of vignetting of your images - the DSLR sensor is simply too big for them.

Also, narrow band filters let through very little light - hardly any (though what they do let through is much less affected by light pollution). That means that you'll need to take longer sub-exposures. If you try doing that with your DSLR, the noise from its uncooled sensor will result in poor images. The DSLR will also only "see" NB light on 1 or 2 pixels of its RGB Bayer matrix - whether it would be able to create a passable image from that is questionable.

Looks as though I'm saving up then :-/

Typed by me on my fone, using fumms... Excuse eny speling errurs.

[Gina]

36mm is the smallest filter size for a standard DSLR. However, they seem to be very difficult to get. I ordered as set of Baader NB filters to use with my modded and Peltier cooled 1100D but after several weeks, I'm still waiting for the OIII filter. As far as I can ascertain, FLO are currently the only UK suppliers of 36mm NB filters. I have a home-made filter wheel to take these 36mm unmounted filters but I'm beginning to wonder if I'll ever get the 36mm OIII. I have Astrononik clip filters in Ha and OIII which are reasonable and I can get satisfactory images with cooled cameras but these are not really practical for a single camera as they are rather a pain to change. Alternatively, you could use 2" filters but these are very expensive.

Personally, I have decided to aim for a CCD astro camera for NB with 1.25" filters in a filter wheel with the idea of probably adding LRGB filters for it in a couple of years time. That I expect to up my image quality considerably. The Peltier cooled DSLR does solve the noise problem to a large degree but a DSLR is always going to be far less sensitive than a mono astro CCD camera. Aside from the difference in native sensitivity a DSLR is always going to be just a quarter as sensitive to Ha with only a quarter of the pixels being used.

For the brighter and larger DSOs a DSLR is a good option particularly if cooled and this has served me well for quite a while and I expect it will continue to do so. But for the smaller and fainter DSOs I know a mono CCD camera is the way to go - particularly as I am keen on NB.

[earth titan]

Thanks all.

Pretty much as I thought. I do love my 80mm frac and would hate to part with it. A replacement to give significant improvements would be v costly.

Guess I better get my shopping list together and start saving - again....

Typed by me on my fone, using fumms... Excuse eny speling errurs.