Gear for Astrophotography

[RikM]

Unless you can visit them in person, the 'in stock for immediate dispatch' tag on Pulsar or Scopes n Skies doesn't seem to mean a lot.

I waited 8 weeks for some binoculars that were 'in stock'.

Have a look at some of the supplier reviews before choosing where to spend your cash.

[Gina]

I like to buy from FLO as they give excellent service and also sponsor this board. I've also had very good service from Rother Valley Optics. Amazon also do some astronomy stuff plus general items, of course, and with a Prime account you can get next day delivery. I've bought lots of stuff from them.

[RikM]

I shop at FLO a lot. Bern at Modern Astronomy is a real hero too.

[frogdr1ver]

We all talk about using dslrs for astro, does anyone use any of the sony nex m4/3 type cameras. Would this help by reducing the cost of the mount as there will be far less weight on it? Are those type of cameras any use?

[E621Keith]

We all talk about using dslrs for astro, does anyone use any of the sony nex m4/3 type cameras. Would this help by reducing the cost of the mount as there will be far less weight on it? Are those type of cameras any use?

I don't think the weight of a DSLR is the main problem here. Small DSLR such as the 1000D weight around 500g, a Olympus EPL2 weight 350g. The weight of the scope is much higher.

Longer focal length will increase the effect of tracking errors, so would a higher pixel density camera sensor. In other word, the 10MP 1000D (DSLR) will show less tracking error than the 12 MP EPL2 (m4/3). A 24MP NEX7 is just asking for trouble.

[Flea77]

Keith is correct and I will add that no matter how good the Sony is (and I am not saying that it is), to my knowledge there are no shutter adapters and/or software that works with them which would make it much more difficult.

If you stick with Nikon or Canon DSLRs there are tons of options as far as software etc to run them.

Allan

[Gina]

Yes, I'm planning to get a Canon DSLR later on for astro imaging. I have a Sony A200 which works but I want more control and a camera to dedicate to the job - removing the IR filter to give better near IR response. I'll keep the Sony for general photography. I can't afford a large CCD astro camera.

[frogdr1ver]

Thanks for answering my question, ive got a Canon 7d so was just curious as to whether a lighter camera would make any difference.

[RikM]

A lighter camera would put less strain on your focuser, but won't make all that much difference to your mount.

[frogdr1ver]

A lighter camera would put less strain on your focuser, but won't make all that much difference to your mount.

Sorry if im sounding thick here what do you mean by focuser? Would a lighter camera not also put less strain on the mount/gears etc or is it because the HEQ/NEQ have more accurate gears also?

[E621Keith]

Sorry if im sounding thick here what do you mean by focuser? Would a lighter camera not also put less strain on the mount/gears etc or is it because the HEQ/NEQ have more accurate gears also?

A lighter camera would put less strain on the mount, but this improvement insignificant, due to the much greater mass of a telescope. The mass difference between the m4/3 EPL2 and 1000D is around 200g, which is small when compared to the 150p's mass of nearly 5kg. The mass of a 7D is higher, but it shouldn't be a problem when a HEQ5/EQ6 can carry over 10kg. You will be fine as long as your scope + camera set up does not approach the mount's carrying capacity.

While the mount may be able to take 10kg, the focuser on your telescope cannot. The focuser is a draw tube at the end of the scope's optical path which moves in and out to focus the camera or eyepiece. When you hang a heavy camera on a focuser, the weight can cause it to move, therefore affecting focus and framing.

I have no experience with the 150p's focuser, so I cannot comment on whether it will be able to handle nearly 1kg of camera.

[frogdr1ver]

Aah right im with you now, thanks for that. Im not sure if ive got my wires crossed here as my plan was actually to use mount plus camera and lens to do the astro photography. I didn't plan at this stage to use it through a scope. Id still like/want an HEQ5 but im steering towards a used cg5.

[E621Keith]

Sorry, I missed your post about using a lens instead. A very sensible choice as most photographic lens have short focal lengths and fast f ratio which should be less demanding on a mount.

A CG5 should handle it as long as the lens is not one of those giant L telephoto.

[frogdr1ver]

I wish i had one of those giant L's ! No the heaviest i have is my Sigma 120-300mm which is 2.6Kg and with the 7D around 1Kg with battery so a max of around 4Kg which would allow for either my 1.4x or 2x convertor and still have a bit of change.

I've read a lot of the links and im trying hard not to jump in and spend £1k's to find out its not for me.

[ScubaMike]

Add up the weight of the scope and DSLR and add on 20%, then see if that is about half the capability of the EQ5.

This AP max load seems to be just going down & down.

A short while ago the concensus of advice seemed to be add up your scope & imaging device and it should be 50% or less of the mount capacity.

Now it is suggested, add up the weight, add 20% and this should be below 50% of the mount capacity.

[Flea77]

I am one of those who thinks those formulas are a bit skewed. I think if it is too close to max you run into problems, but you can also run into problems if it is too light. My personal line of thought is that about 50% would be ideal but less than 75% is acceptable with a smaller/shorter load (for example, a refractor may weigh more than an astrograph, but the refractor is less prone to wind problems and has a smaller center of gravity).

Basically, it all depends :-)

Allan

[E621Keith]

Different manufacturer quote capacity in different way, so that formula won't always work.

Chinese and some American firms over rate their mounts and quoted figure is only good for visual observations. By contrast, Japanese and premium mount manufacturer often under rate their mounts and can carry imaging load upto and in some cases exceed the quoted capacity.

[RikM]

Afraid I missed the bit about imaging with lenses as well. Shorter focal length lenses would make life easier, but a 300mm telephoto with a 2x TC and you are not far short the 750mm focal length of the 150P anyway. I don't know how well your lenses would control colour and star bloat?

If you want to image at that focal length, and with that sort of mass on it, an HEQ5 would have more than enough load capacity.

The focuser on the 150P is not the strongest, but with a 2" T-adapor or coma-corrector in place, plus the little 1000D I haven't had any problems with sag or slipping. It does tend to be one of the first components to get upgraded though.

[frogdr1ver]

Well ive just won an HEQ5 so over the moon that ive got the heavier duty mount.