Use of Barlows and Powermates with astrophotography

[mtfreestyler]

Hi Guys,

It feels like a stupid question because whenever I google it I never get a straight answer.

Can you use a Barlow or a Powermate for astrophotography with a DSLR?

For example using a 80ED with a 2x televue powermate and then the T ring and DSLR.

Also, if you can is there anything that a beginner should know about the advantages/disadvantages of Barlow vs Powermate?

Thanks, Matt

[multiweb]

Absolutely. You can. You'll double your focal length. I do it all the time.
You need a quality barlow to avoid light scattering and reflections. Your exposures will have to be longer.
You'll also need to tighten your guiding as it will be more demanding on the mount.

[mtfreestyler]

Awesome! Thanks.

I was pretty sure you can but I wasn't 100% and before I pick a scope 100% I wanted to be sure.

I will be getting an NEQ6 so that should be able to handle it I'd think

[rustigsmed]

yes the NEQ6 is capable at that focal length, but without an autoguider solution you are limited to ~30-60second exposure max (more likely 30seconds) - so if you have to double your exposure with the increased FL you will be getting dim images because you have hit an upper limit.


cheers

russ

[mtfreestyler]

What I was thinking of was a WO Star71 which is 350mm so with a 2x Barlow 700mm is fairly normal and not extremely zoomed

When I want to go above that I will just get another scope which has a higher magnification and an auto guider is on the cards someday too

[Retrograde]

One thing I discovered about the Powermate (which is an excellent piece of kit by the way) is that getting the right Powermate-to-sensor distance is important.
I tried getting away without the Televue camera adapter using an old 2" camera adapter I had but couldn't achieve focus any which way. As soon as I puchased the TV camera adapter for the powermate (in my case a 4x) it worked a treat. I think the issue I had was being unable to get the camera sensor close enough to the back of the powermate.

[Merlin66]

Pete,
That's an interesting observation with the Powermates....
I have and use the x2.5 PM for solar imaging.
I've used it both with a 1.25" nosepiece/ camera and also with the TV adaptor ring. Didn't make any difference.
No issues, no drama with either.

[Retrograde]

OK good to know thanks - my experience might be specific to the 4x Powermate &/or the adapter I was trying to use to attach to my DSLR.
From memory the T-ring adapter I got was specifically for the 4x.

[Merlin66]

Pete,
the adaptors vary...the 2" x2 and x4 are different.