Posts Made By: Ron Bee

http://members.cox.net/ronby/Observations/061202.htm

Enjoy,
Ron B[ee]

I've been thinking about this question for a long time now. I'm trying to visual how does a high quality (not massed produce) telescope, get its birth from idea, to design, to manufactoring. Let's take an APO refractor as an example ;-). So after reading lots of threads, here's how I ***imagine*** the process to be.

1. Ms. Designer got an idea about a new triplet APO design. Let's say a 104mm f/6 triplet. She sets up design guidelines such as the amount of color correction, spherical aberrations, etc.

2. Run computer simulation using various different glass type (eg. fluorite, etc.)

3. Look up the glass catalog and pick the three lenses. Order them from glass maker. BTW, does the glass come coated or does the manufacter have to coat them?

4. Put the lenses in the lens cell and put them the OTA setup on a bench.

5. Aligning the lenses and check for aberrations.

6. Reject some lenses that doesn't meet minimum requirement.

7. Apply manual (can machine be used?) hand polish to get a more accurate figure.

8. Repeat step 4, 5, and 7 to as close a perfection as possible. Now, here is where I speculate(?) a cut-off as to time (i.e. cost) vs perfection.

9. Assemble the whole thing into a refractor (i.e. focuser, etc.)

10. Perform step 4 and perform final collimation.

11. Pack it up in the box and ship it.

Did I miss any steps? Or is any of the above steps not reality? Can steps 1-6 be performed **only** by master opticians such as Roland Christen, Thomas Back, Al Nagler, Mr. Takahashi, etc.? Or can any "master opticians" (i.e. someone highly skilled and knows what he/she is doing) perform these tasks? Or, do machines do most of these tasks these day, if so, which?

Thanks for helping me visualizing.

Ron the inquisitive B[ee]

PS - No, I'm **not** trying to start a telescope business in my garage, just an overwhelming curiosity ;-). However, I've been thinking about cutting the bottom end of my plastic cup, put an objective lens in one end and an eyepiece lens in another end; this would truly be the Light Cup ;-).

I just stumbled upon this article on my break and almost fell out of my chair! According to the article, the following scopes can see down to the following magnitude:
http://skyandtelescope.com/printable/howto/basics/article_241.asp

100-inch (if I recall) Hubble: 30th magnitude
200-inch Mt. Palomar: 20th magnitude
[4-inch TV-102: 13th magnitude] I add this for scale ;-).

I've been to Mt. Palomar Observatory once in the early 80s and it's very high up. How can the HST with 1/2 aperture see much dimmer than the 200" even if it's in space? No can be, right? Even if the 200" has to see through some air. I've even now accepted that "aperture wins and win absolutely" :-(, until now!

Is the S&T article in error? But if this is correct, then my 4" TV-102 would be able to see down to 17th magnitude or dimmer piggy back on the HST!

Thanks,
Ron B[ee]

With the departure of foggy nights and incoming heat wave, the TV-102 Light Cup got out for a quick viewing last night from 11:30pm to 2:00am. With the moon still up, the LM was a horrible 4.9 in Cygnus (and darkened to mag 5.6 in Sgr after the moon has set). I've always been intrigued by DSO with name (and the Light Cup loves to give a new name); so we visited these open clusters.

NGC 6811 also known as "Hole in a Cluster" was easily found at 22x (40mm Pentax XL), very dim, roughly round group of stars, a good size. Would have easily missed without detail chart. Background still gray at 30x (30mm Ultima). The “hole” is now seen at 44x (20mm TV Plossl) with direct vision and is surrounded by a circle of stars. Averted vision brings many more stars in the hole. Lost impact at 73x (12mm Radian) with darker sky background but hole is
less seen with many more stars in the area of the “hole”. Counted about 30 stars, which are dim enough to look uniformly white. This is an interesting, must see cluster.

NGC 6819 also known as "Foxhead" was also easily napped at 22x, dim like NGC 6811 but seemed to have central brightness, much smaller and more condensed. Form a triangle with the star HD 186255 and HD 186307 at 30x. Looks like a small, loose GC, but compressed. At 73x, it’s impressive in that if I hadn’t known it’s an OC, I would
have though it was a GC. Appeared completely resolved at 110x, too many stars to count, guessing < 100 stars. Does anyone know how this OC got the name “Foxhead” ‘cause I reason seems to escape the Light Cup (we didn’t see any shape). Oh, I get it; the Light Cup muar have been looking down the wrong fox hole ;-).

Alas, NGC 6888 (the "Crescent Nebula") was nowhere to be seen even though I've located the star field precisely. Perhaps, this object can be seen with filter and on moonless night.

Believe it or not, I haven't seen the Coathanger (Cr 399) yet :-(. But the Light Cup did take me to NGC 6910, dubbed the "Mini-Coathanger". Located precisely with detail chart at 22x. I mistook the stars HD 229196, HD 194241 and HD 194279 to be the coat-hanger without the hook. At 73x, the coat-hanger shape is quite apparent with the coat-hanger being the stars HD 194241 through HD 194279 with a total of 8 stars. The hook is made up of stars GSC 3156:1857, GSC
3156:744 and GSC 3156:850. Best view. Still nice at 110x (8mm Radian). Since this OC also has the name "Wishbone", I also noted that the star HD 229196 together with the rest of the stars I noted did looked like a sort of "Y" shape wishbone!

Before packing it in, the TV-102 Light Cup did make a wish to NGC 6910 for an excellent weather after the full moon for a rematch with Pluto and the NGC 6118 arch nemesis ;-)

Ron B[ee]

Guess what I found on SAA today. I installed it and wow!
http://astrosurf.com/avl/UK_index.html

Ron B[ee]

After several attempts at NGC 6118, the most difficult object in the Herschel 400, and nothing but failures so far, tonight, my 4" TV-102 Light Cup decided to tackle NGC 6380, which is reputed to be the 2nd ;-) most difficult object in the Herschel 400. The Sky and SEDS listed this open cluster at magnitude 15! Whoa, wait justa dogon
minute, I told the Light Cup; this is insane. But the Light Cup's research dugged up some observation that the OC is around mag 9.6. OK, why not. The LM around the area was only 5.0 with sky glow and light pollution from the south. Armed with detail zoomed in printed chart and photo mirror reversed to match the view, the Light Cup and
I spent one hour on this object alone!
http://www.seds.org/~spider/ngc/ngcdss.cgi?obj=NGC!6540&r=18:06.3&d=-27:49&e=J2000&h=15&w=15&f=GIF&c=none
Please import it into MS Paint and mirror reverse the image for the observation below.

I can see why this object is the 2nd most difficult because it was hard to find despite having a detail printed chart. One look at the photo should convince you of this as well :-(. After the star field has been located, it was no where to be seen at 22x, 30x, 44x, 73x! The Light Cup got really worry but switched its eyeball to the 8mm TV Radian (the Planetary Nebula Nabber) at 110x and viola, hooked this
fine open cluster into its OTA. The view is much better a 146x (6mm Radian) showing the asterism of 6 stars at the lower left hand corner of the photo: GSC 6850:3231, GSC 6850:3442, GSC 6850:1481, GSC 6850:3253 and a mag 8.9 HD 165180. The OC is enclosed by a triangle made up of the stars: HD 165180, GSC 6850:2111 and a dim GSC 6850:1614. Some stars could be seen inside the OC with averted
vision. The shape looks irregular with brighter center. This bright center is probably the bright group of stars near the center of the photo. The very best view at 176x (5mm Radian) which is incredibly brighter than at 146x. 2 more dimmy stars popped in: GSC 6850:2110 and GSC 6850:1199. Some stars in the central portion of the OC can
now be seen with direct vision. I would estimate that NGC 6540 is much brighter than mag 15 but dimmer than mag 9.6.

I also noticed a group of stars that looked like another loose OC as seen at the bottom of the photo. Consulting The Sky, it doesn't appear to be any open cluster in that area.

Checking with The Sky software later, I found that the OC isn't plotted where I saw it! I carefully sketched the OC and the stars during the seesion; besides the photo doesn't lie ;-). For you guys who are H400 veterans, I would appreciate any comment.

I recommend this very challenging open cluster to everyone and especially to those who conceived of OC as being dreary and would surely alter his/her notion as being sweaty (meaning working up the sweat just to see it ;-).

Ron B[ee]

I finally got the Lumicron 2" UHC and 1.25" O-III filters today and the weather holds. Tonight, the purpose was to try out a few objects and not spending my usual quality time on each object.

M57: The donut hole is easier in both filter.

NGC 7000: Finally, I could see the nebula! But I admit that it wasn't as spectacular as I thought it would be. The filter just made the nebula visual and it was still dim. Can't tell if O-III was better but it was surely darker.

NGC 6334 (Cat's Paw Nebula). I reported seeing it a few weeks ago without filter. Tonight, I couldn't see it without filter. But then I didn't try to match the star pattern as I did a few weeks ago to nail its precise spot. UHC brought it out but still very dim. Can't say that I saw it with O-III, too dim.

M8 (Lagoon): Wow, I can now see the northern portion of the nebula with ease via the UHC. The O-III seems to bring out more, but not 100% sure. Then, I notice something strange about the stars (more later).

M17 (Swan): Wow, much more it is visible through the UHC and seems more intense with the O-III.

O-III definitely is dimmer with darker sky background. I couldn't believe I've been "keeping the faith" without filter for more than a year! Lookout Rosette, Witch Head, Flame, etc. nebulae; your days are numbered. However, I can see that it's gonna to take a lot of practice as to how to use the filter.

Here's the strange thing. While looking at M8, I noticed that I couldn't bring the star to focus with the 2" UHC screwed into my 2" TV Everbrite diagonal. So I removed and place it in front of the eyepiece and viola, no problem. I tried with Antares and here's a real strange result. Out of focus cause the star to be elongated into a line on both side of focus when screwed into diagonal. When place into front of the eyepiece, all is ok. This is with the 2" UHC filter. What is wrong? Is the filter defective? With the
O-III filter screwed into my eyepiece, the stars looked fine.

Thanks,
Ron B[ee]

This is the start of the 4" TV-102 Light Cup new Hot Tip series ;-). Only "red hot" objects will be featured!

Last night while using my HOPTO mount ;-) with my 40mm Pentax XL eyepiece (22x) yielding 3 degree FOV to get to NGC 6712 & IC 1295, the Light Cup passed M11. Now, I've seen M11 many times but this isn't the hot tip ;-). But what's this asterism near M11? Why what do you know; it looks like the neck, the head and the bill of the Duck! Starting at the star HD 174209, following the shape of the
duck’s neck to the duck’s head at the star HD 172768 and curve around to the edge of the duck’s bill at the star HD 173693 and follow the end of the bill at the star HD 173219. Can you see it? The whole asterism and M11 just about fit into the FOV in its entirety. You may need at least 3 degree FOV to appreciate its form. Henceforth, the TV-102 Light Cup christened this asterism, the "Duck's Portrait" ;-).

Ron B[ee]
PS BTW, while there take time to observe NGC 6712 GC and IC 1295 PN. The UHC filter really struts its "ultra" stuff. And my TV-102's hat off to the TV Pronto; it's unbelievable how the dim IC 1295 could be seen through it! http://homepage.mac.com/joebergeron/scopes.html

http://members.cox.net/ronby/Observations/070702.htm

Enjoy,
Ron B[ee]

http://members.cox.net/ronby/Observations/070802.htm

Enjoy,
Ron B[ee]