Skywatcher 200 Dob Eyepieces

[ONSLOWE]

I have just received my Skywatcher 200 f5.9 Dob on time and in perfect condition via First Light Optics (Thanks Steve !), collimation looks very near perfect so I will leave it alone. Now the usual questions about eyepices. I would like a 2" Widefield for a bargain price and was wondering which to choose between the 30mm and 40mm Revelation items. Is the 40mm too much for the scope or my eyes ? (I have good eyesight). For planetary work I was thinking of a Baader Ortho of either 7mm or 8mm which I intend to use with a Meade 140 Ed barlow when I find one at the right price. I am thinking that the Barlowed 7mm might be too much magnification for the poor atmosphere and light pollution that we get where I live. The scope went together easily but I am not sure if the Azimuth feels a little stiff even with the centre nut slackened right off, the teflon pads seemed a bit small for the base, is this normal ? I have never tried a Dob mount before so cannot compare with any others, the Alt is very smooth by comparison. Now I have the scope the clear skys of the last couple of days immediately turned to cloud and snow is forcast, I kid you not

Thanks in advance for any advice.

Martin

[geppetto]

Martin

Congrats on the new scope have lots of fun with it...

Re the AZ movement, try a wipe of squirt furniture polish on

the pads and on the underside of the top board.

Also, its worth making some washers out of plastic milk container stuff

and fitting one between every rubbing surface on the AZ bolt.

eg, between any metal washer and wood board.

Can't advise on eyepieces cause I can't even make my mind up

what I need three years into the hobby

[Andrew*]

Hi Onslowe. I don't know if I've welcomed you to SGL yet, so WELCOME!! Hope you enjoy it.

With regard to EPs, a 40mm should be fine in your scope. Its exit pupil is 6.7mm, which should be quite comfortable, and it's got a nice open FOV. I'm lead to believe the Revelations are a good buy.

For planetary, you're right about the Baader orthos, no question, but 7mm barlowed is asking too much from our skies. You may occasionally be able to barlow the 8mm, but even that's pushing it. I think you'd be best off buying a 9mm and barlowing that giving 133x and 267x, or if your skies will never be good enough for 267x, a 6mm would be ideal.

HTH

Andrew

[The Warthog]

A 40mm ep will give you about 30x, which is a great power for searching, and looking at larger areas and things like M31. I get 23x with my longest ep, and use it almost exclusively for searching.

[FLO]

This might help

[ONSLOWE]

I am now thinking I will forget the Barlow for now and get the 6mm as suggested above,the skies here are quite bad, mag 4.5 on a good night, lots of light and atmospheric pollution. The scope came with average quality 10mm and 25mms eyepieces so that might be enough 1.25" for now (wallet still feeling the strain from Christmas !). I am still unsure about the exit pupil for the Revelation 42mm being too large at 7mm compared to the 30mm at 5mm, my eyes will never get fully dark adapted at home due to neighbours lights etc though the helpful graphic by Steve makes me want the 42

Will have to have a think about it whilst the clouds are about so that will be quite a while then

Cheers,

[FLO]

Finally got around to it....

[ONSLOWE]

Thanks for that Steve, as you now know I decided to get that exact combination from you and I look forward to getting them later in the week. Many thanks for remembering the post despite having astrofest on the go.

Cheers,

Onslowe