Posts Made By: Jake Jacobson

My most recent Jupiter attempt.

The seeing was pretty shoddy, and I certainly overprocessed , but I am just happy to be able to be imaging again after 2 months of either clouds or wind here in S. California!

-Jake

I have the generic CG-5 mount with the polar alignement scope (you know, the one that uses three adjustment screws and is a real pain to align....)

I am tired of re-aligning the polar scope which inevitable gets bumped every so often while in transport. I am wondering if anyone has ever figured out a way to permanently set the polar scope in the retaining collar once it is aligned properly......

I have been contemplating getting a nice 2" low power superwide eyepiece around 30mm length for use with my newtonian. The one I have been considering is the 31mm GTO Proxima, which I believe to be an erfle, but I am not sure. I haven't yet had a chance to try anthing longer than a 25mm in my newtonian before, so I have no idea how an eyepiece like this would perform with the fast (f/5) optical system. It is my understanding that longer "ultrawide" eyepieces like this can be problematic in fast newtonians. Is this too long for my telescope? What kind of problems should I expect to experience?

Thanks!

Does anyone know if this polar illuminator:

http://www.buytelescopes.com/product.asp?t=&pid=4794&m=

will fit on the CG-5/EQ-4 mounts?

Thanks,

Jake

Got mine in the mail today. Boy is it big, and appears very nicely made. The coatings are deep green and look very nice. It came packaged in a nice bolt-style case with endcaps.

Haven't even got a chance to try it out yet in the scope - but looks and feels like a much more expensive EP - really nicely done.

The only suprising thing is that there is no indication of the country of origin anywhere on the EP.

I will be testing this in a moderately fast (f/5) 8" newt, and will post a review once I have had the chance to use it a few nights.

-Jake

This is a sum of 7 x 15 sec shots (darks subtracted) taken with a SC modified Toucam Pro(non-cooled, no amp-off) and an 8" LX-200 (w/ f/6 focal reducer) in alt/az mode (which gave me a little elongation in the stars.)

-Jake

Although my EP collection is rounding out quite nicely these days, the one focal length that I am sorely missing is a good, sharp, 10mm EP with good light throughput. My current 10mm EP is a simple 4-element plossl which has good throughput, but not the best contrast/sharpness/eye-relief/fov.

I really would like something with a decent fov and better eye-relief, but since my primary deepsky scope is an 8" newtonian, light-throughput is very important to me, so Televues are out of the question.

I recently borrowed another observer's Pentax XL 10mm, which had fantastic light throughput, and a nice fov. The Pentax is a bit more than I wish to spend at the moment. So I am basically looking for something with a similar FOV, that is sharp, and has similar light-throughput. I am certainly willing to sacrifice off-axis sharpness in exchange for better light-throughput.

I have used a 10mm speers-waler in a different scope than mine (15" dob), and remember it as being quite impressive in all areas, but since I was using it in a larger scope, I can't really judge the light throughput. My understanding is that it is a 7-element design.

Does anyone have experience on how the speers-waler compares to the Pentax regarding light-throuput? Are there any other good candidates for a 10mm deepsky eyepiece in the under $200 category?

The other one I am interested in is the new Apogee widescan 9mm - but I know absolutely nothing about the performance of this eyepiece.

-Jake

Just a curious question....

I see many classified ads here in Astromart for EP's in which folks seem very concerned about setscrew marks on the EP barrel. I am curious as to why.

I, for one, have never cared about setscrew marks when purchasing a used EP - I am much more concerned about optical quality and housing appearance. It seems to me that any EP I purchase will get setcrew marks from using it anyway. Furthermore, I have yet to see setscrew marks that are more than very light surface dimples - and if they really were bad, EP barrels are cheap to replace anyway.

Does anyone else really care about setscrew marks?
Why?

-Jake

I am contemplating ordering a mirror for a dobsonian project, and am looking at mirrors in this size.

It seems there is a considerable jump in price between a 13" and 14" mirror.

I have looked through many 14" mirrors, and think I would be happy with that size, but given the price difference I would like to order a 13" mirror if there is not much difference.

Is there a big difference between these apertures? Will I end up wishing I had sprung for a 14"?

-Jake

Well, kinda!

Actually, most of these aren't mine. Just pictures from the most recent new moon Saturday at Mt. Pinos. For those who don't know, Mt. Pinos is one of the best dark sky sites in Southern California, and is so popular that every new-moon weekend is like an impromtu star-party.

-Jake