Focal reducer vs 2" eyepieces for a f12 Mak

[chuenmanc]

Hello

I was wondering if anyone had any advice for getting the best DSO ability out of the Skywatcher 150 Pro I have. It's a f12 1800mm focal length, 150mm aperture Mak. I bought a 2" adaptor and 42mm eyepiece with it, which does help, so I've been thinking about getting a 2" diagonal for it, as I don't think it will get much use otherwise.

The alternative is getting a focal reducer and sticking to the 1.25" format. The Celestron f6.3 is the one recommended, but is a bit pricey, so i fancy trying the cheaper Atik or Antares ones, that are nearer £25-30. Does anyone have any experience with these? And with focal reducer vs 2" eyepieces as a method of getting a wider field? Andf finally, is there anything wrong with using wide field eyepieces + focal reducer?

Thanks!

Chuen

[GazOC]

Hi,,

The Atik/Antares models are for imaging. They do work with EPs but you'd ahve to change the focal reducer everytime you change EPs.

The Celestron/Meade ones can be left in the diagonal.

Gaz

[FLO]

http://stargazerslounge.co.uk/index.php?topic=226.msg30671#msg30671

[MartinB]

That's taken him full circle Steve! apart from buying another scope which will help a 6" Mak deliver on DSOs focal reducer or 2" EPs. He has some 2" EPs already but wants to know if he would be better off with a reducer. Interesting question. Does anyone know the answer.

Martin

[GazOC]

The Mak can "do" deep sky with a focal reducer (thats the way I'd go) it's never going to be great because it's not really designed for that task, whichever way you go it'll be a case of "making the best out of it".

One thing to watch if you go down the 2" route is to make sure the Mak does have 2" of clear room, my Intes is threaded for 2" but the hole in the mirror is only around 1.75", so this affects choice of eps/ FOV. I've no idea if this is the case with the Skywatcher but it's something to check.

[chuenmanc]

Sorry to have this discussion in two threads! And thanks for summarising MartinB - you made it clear to myself too!

Gaz, your point about 2" is a good one. I wondered if I wasn't getting the full benefit of the 2" eyepiece because I was having difficulty finding a spot for my eye where I could see the whole field of view. I put it down to inexperience, but thought it could have been due to not all the eyepiece being illuminated by the light from the scope, if you see what I mean, and which *I think* is what you mean. I'll see if I can measure or guess the size of the mirror opening.

I'm keeping an eye out for a second hand 1.25" wide field eyepiece to see what it's like. Then if I get a focal reducer the extra field will be a bonus. And I'll probably join the local astrosoc to see if there is anything I can borrow to find out what works best.

[GazOC]

Hi cm,

If you just take the diagonal off and look "into" the scope, you'll be able to see if there is any stopping down.

Gaz

[chuenmanc]

Hi there

I unscrewed the eyepiece/diagonal holder off the telescope, and measured the opening. 24.5mm diameter. Smaller than I was expecting, so I imagine 2" eyepieces may not be the answer. In the meantime I bought a Meade 12.4mm Plossl, and am looking for a second hand apo barlow (hearing good things about the Orion/Antares shorty), to try out higher magnification.

So far the Mmeade eyepiece seems slightly better than the supplied Skywatcher ones, but not amazingly so.

And also keeping an eye out for a focal reducer, and a 32-35mm eyepiece to use with it, on the Astro Buy & Sell site.