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Posts Made By: Jeff Blazey

October 18, 2008 12:56 AM Forum: Refractors

Eon 120 interferometer results

Posted By Jeff Blazey
Interesting!

How about posting copies of the Focaultgram, Ronchigram and the picture from the interferogram? That would complete the picture.

Jeff

November 9, 2008 07:07 PM Forum: Eyepieces

Budget wide angle EP suggestions?

Posted By Jeff Blazey
Edmund RKE 28MM. Cheap, good, readily available, decsnt field of view and will work well at F8.

Also, try the Garrett SWA 20 & 15 MM as well as the new Sterling Plossls.

Jeff

November 17, 2008 02:47 PM Forum: Refractors

Collimation question, over tightened? with pic

Posted By Jeff Blazey
Keith:

I've the same issue with a Meade 102ED I recently picked up. What your drawing describes is astigmatism. Note that the red and blue break out at 90 degrees from each other. I bet that the inside and outside of focus star images at high power (150X or more) with 4-5 rings are elliptical and at 90 degrees to each other too. Also if you check with a Cheshire you'll see the "dots" rather widely spaced. Using the collimation screw pairs on the front of the cell to overlay the dots in the Cheshire view yeilds the coma o))))

The ED element needs to be recentered.

What you need to do is collimate with the Cheshire first then carefully remove the three small screws buried on the OD OF THE RIM of the cell close to the collimation screw pairs. Once removed you will have access to another screw in each hole. These are the centering screws. I would back off each of those by say an 1/8 turn. Then, watching the coma image, gently adjust the screws to remove the coma then re-insert the outer screws and gently tighten them to the recentering screws. This locks the inner screws into position.

I dug up the instructions on the yahoo group but have not yet tried it with mine. Looks fairly straight forward.

Good luck

Jeff

December 1, 2008 04:01 PM Forum: Astro-Physics

Moon, Venus and Jupiter from Hawaii

Posted By Jeff Blazey
As I'm sitting here typing looking out the window at the greyness, and wind whipped snow falling, one word comes to mind

HAWAII!!

Don't forget the sunscreen. 8)

Jeff

January 1, 2009 01:06 AM Forum: Astro-Physics

Big One - first 6 months

Posted By Jeff Blazey
I do have to say I love the retro look of the old Altec-Lansing woofer glued to the beer can bundle counter weight.

Cool...err...C-O-L-D.

Did you have to specially bias the manufacturing tolerances to handle the thermal shrinkage at such cold temps?

Jeff

January 1, 2009 01:10 AM Forum: Off Topic Discussions

come look through my TEC200

Posted By Jeff Blazey
Mike:

I double-dog dare you to stick your tongue on the tube assembly!

Jeff

January 4, 2009 01:10 PM Forum: Refractors

Diagonal Comparisons

Posted By Jeff Blazey
I've had 4 AP Maxbrights, 3 of the Televues, several rather generic Celestrons and 3 Intes, all 2".

The APs are well put together and have a great "feel" to me. The Televues were a slight step down in that regard. The Intes another step lower and the Celestrons "servicable".

There were various level of mis-alignments when using a Glatter laser. 3 out of 4 of the APs were spot on, as were all of the Intes, 1 of the TV and 1 of the Celestrons. All others were sligthly mis-aligned but I don't think that matters too much as I could get all of them out of alignment with the scopes optical axis by simple moving them around a bit in the focuser.

Optically there were no dramtic differences between any of them except I felt 2 of the Celestron diagonals were not QUITE as sharp as the AP or Intes which subjectively were the top of the heap optically. An interesting side note for the Intes is that the coatings seemed to add a very slight/subtle yellow tint which worked very well with my achromats.

Based upon which ones I've kept I'd rank the APs and Intes as equals and on top. I sold the TV's as the Intes were just as good but cheaper on the used market.

Hope this helps.


January 9, 2009 01:35 PM Forum: Refractors

Objective focal lengths

Posted By Jeff Blazey
Just measure it.

For shorter FLs I simply use a yard stick with a sheet of white paper stuck to the "bottom" end. I point the "top end" of the stick at the sun and move the lens along the stick until I get a sharp image of the sun on the paper. I then write down the number of inches from some mechanical feature on the cell that I'll use as a reference. When that's done I put out the paper fire.

Lately though, there has been no sun visible to point at.

Jeff

January 16, 2009 12:28 PM Forum: N.A.S.A.

New light on Mars methane mystery

Posted By Jeff Blazey
Like any large organization I bet there is a large diversity of opinion on this subject inside NASA.

They put their game face on for the press conference and came out hedging but I bet there were some really intense "discussions" that went on before hand with some highly qualified people absolutely convinced that the methane is biological in nature.

We shall see how this evolves...pun intended.

Jeff

January 16, 2009 08:14 PM Forum: Equipment Talk

How cold is too cold?

Posted By Jeff Blazey
Interesting replies and I've always had such reservations after a 6" F10 Jaegers lens developed a small clam shell crack one night when I took it from the 70 Deg.F interior of my brother in law's house out to the -25 degree ambient one Christmas eve. That was my lump of coal.

That type of sudden shock where the aluminum structure can shrink very quickly and pinch the optics would be my only concern.

Jeff

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