Posts Made By: Ron Bee

I went back to Peter's 10" SCT and he showed me M104. Wow, it was so easy to see the dark lane both with direct and averted vision! I've never been able to see this through my 4" from my backyard (never tried it at dark skies yet) as there's quite a bit of light pollution from my backyard southern sky.

I must admit, confess, concede and consent that I lust after Peter's 10" SCT. It's so much nicer to be able to observer from the rear end, sitting down ;-). Also, the details in the DSOs were so much easier to see! However, after Peter told me about its 65 lbs weight (almost 1/2 as much as my body weight :-(), a touch of reality hit me
like a jaw crushing fork arm! But what about the C9.25 - umm.... I can even get to like GOTO ;-). I'm now wondering if the larger aperture SCT (say 10" and above or perhaps even 9.25") have really no issue at all with the central obstruction as the contrast seems to look fine to me. I walked away from the star party more convinced
than ever, 200% convicted, that those large ladden laden Dobs are never for me! No way no how!

My family and I had a lot of fun tonight with various telescopes. Admittedly I was hoping to see a 6" AP APO, but such was not the
case :-(.

Lastly, I know what you guys are thinking or thinking of asking ;-). Would I ever be satisfied again with DSOs through my 4" TV-102 Light Cup? Well, the answer is ... ;-). I'll tell you this much. Seeing these favorite DSOs of mine through these big bad buckets just made me appreciate my runty little 4-incher even more ;-).

Ron B[ee]

Hello there Ed,

This formula is still way too conservative. I plugged in a=4, p=7 and LMe=6 and I got LM 11.8 - way too conservative for my 4" TV-102 APO refractor, currently at the observable LM of 13.5 (this was before my Pluto attempt this morning). IMHO, I'm afraid there's no simple formula to predict **accurately** the visual limiting magnitude of the telescope as there are so many variables such as the eye ball ;-), the fine vs so-so optics, telescope design itself, the transparency, and the technique (i.e. skills) employed by the observer.

Ron B[ee]

My 4" TV-102 Light Cup has been trying to bag NGC 6822, a dwarf galaxy famously known as "Barnard's Galaxy". This galaxy literally dwarfed my already runty Light Cup last year. Night after night, failures after failures from my backyard. I even employed Bill Ferris' beautiful sketch, but to no avail. Just stars and gray background everywhere. Low power was no go. Upping to medium power of 73x and
more was no good :-(. You won't believe how many nights I tried last year! So Barnard's Galaxy become another one of the Light Cup's nemesis!
http://hometown.aol.com/billferris/n6822.html

Well, this morning (06/04/03 8:15UT) after my Pluto session and under the dark sky of mag 6.5 (never came close to this from my backyard) at an altitude of 6000 ft., I limped to the target and what do you know: it's right there where it should be at 22x. Looks like a brightening against the background sky. 30x gave the best most contrasty view with the central portion *slightly and I mean slightly* brighter than the rest of the galaxy, oval looking, slightly grainy looking with a few stars seen in the galaxy with averted vision! No core whatsoever and it's large - which is why it was impossible from my backyard. 73x was no good; so indeed this galaxy lives up to its reputation of needing low power. Again, dark sky contrast was the decisive factor. All in all, another nemesis nullified by the now tall in the saddle Roadside Light Cup ;-).

What amazes me is that it was discovered by Barnard with his 6" refractor (his first profession telescope?). Being that the galaxy lies in the rich star field of Sgr., I just can't see how he could have ever discovered this so elusive galaxy. It was sure darn hard just to bag it knowing where to look!
http://www.seds.org/messier/xtra/ngc/n6822.html
(don't let this nice and bright photo fool you ;-)

Ron B[ee]

... with some examples from Jay Freeman's article (since perhaps not every one read everything ;-). Jay wrote:

"Let me illustrate the benefits of observing skill and experience. At a star party I once attended, a relatively inexperienced observer had bought a 15- or 18-inch Dobson, and was looking for the Horsehead Nebula. It's pretty faint, and he was having trouble locating it. I know the field for the Horsehead, so I offered to help. Yet when I stepped to the eyepiece, what do you know? He had it centered! The object he was looking for was right square in the middle of the field of view, but he couldn't see it!

Now, the reason I could and he couldn't was surely not that I have superior vision: I know that I do not, because I have compared notes with many other experienced observers, and we can all see about the same things in similar circumstances. But I do have a lot of experience, and I have deliberately worked hard to try to develop my observing skills. In my opinion, that made all the difference. I hope you will excuse my talking about it, because I am not really boasting -- there's nothing I have learned to do that you can't learn to do just as well, and perhaps knowing of my experiences will make you decide to try.

Let me give another example. At another star party, the owner of an eighteen-inch Dobson had chased down NGC 6822 -- Barnard's Galaxy -- which is fairly large in angular size, but has a relatively low surface brightness. It is fairly difficult to see, and the owner of the big Dobson was legitimately proud to have located it. I asked if he would like to see it in my telescope, and led him over to the 90 mm refractor that I had set up on the other side of the observing area. At first he couldn't see a thing, but after I reminded him about averted vision, shielding the eyes from stray light, and a few other tricks, he did indeed see the galaxy in the smaller telescope."

Ron B[ee]

I would *STRONGLY NOT* recommend it, Robert. Imagine one slip and you scratch the lens :-(! If you must, here's some guide how to clean the optics.
http://www.televue.com/engine/page.asp?ID=143
http://www.astro-physics.com/tech_support/refractors/care_refractor.htm

Both AP and TV don't recommend cleaning a lot. In fact, Roland Christen wrote somewhere that it's more important to keep the eyepiece clean.

After the Mars season, I do plan to send my TV-102 into Tele Vue for cleanup and a massage job ;-) due to overuse :-(, i.e., I use mine a lot!

Ron B[ee]

Hello there Michael,

APO heist - you mean ;-).

I've often mentioned that dark sky is the 4-incher best friend ;-). I'm so glad you're finding out new joy from your 4-incher! There are many DSOs just plump waiting for
you to pluck ;-). Be sure to arm yourself also with UHC (and perhaps also O-III) "magical" filters; they'll bring more joy to those planetary and emission nebulae.

Ron the 4-inch Tall Evangelist B[ee]

You have sent in your TV-102 much wisely, Dan. Hopefully, you did put in a special request note, asking for Al himself to clean it for you ;-).

Since I left mine in the living room, I'm thinking of getting on of those telescope cover or some thing to cover it up to fight the dust when not in used. So when it comes back, you may think about something similar.

Ron B[ee]

I've stumbled upon this excellent article by Barbara Wilson!
http://spacsun.rice.edu/~has/200108gsw.pdf (scroll down)
The sketching part is very inspiring as well as I had no idea such a highly skilled observer's first observation of Mars was to put it in her own words "disappointing" :-(! Also, I had no idea where the "magical" 42mm circle comes from; thanks to Barbara's article I know now :-).

Ron B[ee]

http://members.cox.net/ronby/Observations/TV-102-kick-Dobs.htm

Ron B[ee]

http://members.cox.net/ronby/Solar-System/Mars-TV102-PDHQ-063003.htm

Enjoy,
Ron B[ee]