Looking for more eyepieces with little money

[Charic]

......if it helps anyone intending to buy a reflector, and choosing their first EP upgrade, looking at the specification label on the scope, take the aperture size as your practical maximum power, and buy your high power EP based on that power limit. The focal length of the scope divided by the aperture gives the focal ratio, matching the size of your high power EP.

Yes, you can exceed this limitation but its as good a place to start as any, and works well .

[brantuk]

I think your view of M13 is not going to be determined by "seeing" alone - it's also a matter of aperture that determines how far towards the center you can resolve stars (and there's a lot of them in that glob). Have a look at the aperture comparison towards the bottom of this website then bear in mind you have only 2/3 of their smallest  aperture.

http://www.obsessiontelescopes.com/

Hth

[Magrene]

Well for seeing it's pretty poor her this time of the year. The humdity really isn't ever low. I actually went down to the beach last week end with a friend and we setup my scope on the sand. Seeing was as good as it was going to get here in the summer there. Was really cool because most of the southern sky was clear and free of most of the light pollution. We did end off being kicked off the beach by the state police though who said we had to stay in the parking lot. Good thing he didnt ask if I had a permit. But I noticed when we were leaving that the outside of the tube was wet. So I've decided to keep my scope indoors until a night with lower humidity. As I can't imagine it's good for any of that condensation to get on the primary or secondary and with how wet the scope was I am surprised it didn't. Does more relief help with condensation because both my 6.2 and 25 fog upcoming. The 6.2 fogs up within minutes. The 25mm after 20-30 mins. I don't even really take my 6.2 out anymore because of the fogging up the occurs.

[brantuk]

The beach might not be a good idea for a scope. One SGL member had his mirror start peeling due to the sand in the air wrecking the coatings over about 18mths.

If you're getting condensation then you may need a dew heater for the secondary. It also helps to have a dew shield - and sometimes a fan on the back of the primary to keep the air moving over the surface and prevent moisture forming.

[SpaceWalker]

How is 18 for looking at objects like m13? My 25mm is just not enough mag to make out much of anything.

I don't have this eyepiece, but I've read a number of reports about FC in it. The same problem found in the 18mm Celestron X-Cel LX and Meade HD-60. Looks like the 18mm is the weakest eyepiece in these three optically related  lines. If you can try it before buying, just do it. I'd suggest you to get the 12mm Agena Starguider ED/AT Paradigm rather than the 15mm or 18mm. This magnification (100x) is a sweet spot for 8" f/6 Dob and good for many DSOs and you can 2x barlow it to reach another sweet spot in this scope, 200x. The 8mm should be fine.

As for M13, most of globular clusters require high magnification like 200x+. Actually, you can't resolve M13 into stars satisfactory with your 8" instrument, I guess you need 12". Although, my 6.5mm HD-60 frames it nicely on my 8" Dob. I guess, that your 6.2mm Sirius plossl should be fine for M13 when the weather cooperates, just try it.

P.S. BTW, do you have Stellarium? If not, download it and try various scope/eyepiece setups on DSOs including M13.

[Magrene]

I don't have this eyepiece, but I've read a number of reports about FC in it. The same problem found in the 18mm Celestron X-Cel LX and Meade HD-60. Looks like the 18mm is the weakest eyepiece in these three optically related  lines. If you can try it before buying, just do it. I'd suggest you to get the 12mm Agena Starguider ED/AT Paradigm rather than the 15mm or 18mm. This magnification (100x) is a sweet spot for 8" f/6 Dob and good for many DSOs and you can 2x barlow it to reach another sweet spot in this scope, 200x. The 8mm should be fine.

As for M13, most of globular clusters require high magnification like 200x+. Actually, you can't resolve M13 into stars satisfactory with your 8" instrument, I guess you need 12". Although, my 6.5mm HD-60 frames it nicely on my 8" Dob. I guess, that your 6.2mm Sirius plossl should be fine for M13 when the weather cooperates, just try it.

P.S. BTW, do you have Stellarium? If not, download it and try various scope/eyepiece setups on DSOs including M13.

Dont have stellarium but I have an app called starwalk on my iphone. Works really great has a night time mode as well have been using it every night I observe.

[Magrene]

The beach might not be a good idea for a scope. One SGL member had his mirror start peeling due to the sand in the air wrecking the coatings over about 18mths.

If you're getting condensation then you may need a dew heater for the secondary. It also helps to have a dew shield - and sometimes a fan on the back of the primary to keep the air moving over the surface and prevent moisture forming.

Yeah well at least in the summer. I can keep it in the parking lot further away from the beach in front of a dune. I think that will be best. Here the light pollution is so bad that observing from my yard is quite difficult since I can't see most of the stars.

[rwilkey]

Ok I am thinking about getting a 15mm and an 8mm astro tech paradigm. What does everyone think?

Hi there, that is a great and wise choice, you will be suprised at the great quality.

[bamastar]

I was kinda in your shoes a couple months ago. I had a big gap between my 20mm Orion Sirius plõssl and my 9mm Sirius plõssl. I went with the Explore Scientific 82° 11mm and got it from b&h photo out of New York. This has become my "goto" ep. I love it for DSO. There is a small bit of coma in my f/5 but it really doesn't bother me at all. They are also on sale right now for $135.