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Dolphin Head Nebula Sh2-308

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Posts Made By: Jeff Blazey

April 24, 2007 10:48 AM Forum: APM

New APM Project starts : 180 mm f/6 ED Apo

Posted By Jeff Blazey


I hereby volunteer for beta testing of all models and prototypes.

I won't charge much....Oh shoot, I'll do it for free. smile


April 24, 2007 12:57 PM Forum: APM

New Product : APM Deluxe Dovetail Rails

Posted By Jeff Blazey


Great! Say where are the spot diagrams?


May 8, 2007 02:09 PM Forum: Pictures of Me and My Telescope and........


Posted By Jeff Blazey


You will have a BLAST with the Intes. Great optics & portable.

I love mine.



May 23, 2007 06:15 AM Forum: Equipment Talk

refractor tubing -sizes, tube currents, etc.

Posted By Jeff Blazey

Hey Kreig:

I'm not sure what F ratio you're working with but here is my experience.

First, I would not worry too much about tube currents with AL. It tends to cool quickly and you can always vent the tube and even use a SMALL active fan just to get the air gently moving.

Second, depending on the F ratio and mechanical stack-up of the lens cell (basically the cell design and the ID of the cell as it butts up to the end of the tube), using the 10" O.D. tube should not be a problem. There should be no vignetting. The first baffle placement gets more interesting though and you will want to flock the tube up to the first baffle.

The advantage of going to the larger tube is indeed stiffness, plus you can put the first baffle closer to the objective.

Personnally, I would go with the smaller tube.

Baffle design is based upon the good old algebra equation (Oh good night...he's talking MATH now :S ):


Where B is the fully illuminated image spot you've chosen at focus.

M is the "slope" and is the lens diameter minus the image spot size, all divided by the focal length.

I usually just pick 4-5 baffle sizes in whole inches and "solve for X", which is the distance from the back of the lens to where that particular baffle should be.

Not too hard really.


May 30, 2007 04:56 AM Forum: After Dark

Weather balloon

Posted By Jeff Blazey


See my thread below dated May 8th. Your picture is exactly what I saw. smile


June 18, 2007 07:06 AM Forum: Refractors

Please help me star test this scope

Posted By Jeff Blazey

Yeah, yeah, yeah, a lot of talk but does he have a nice scope? I agree with John and would say yes. I see nothing that jumps out as a problem. Sure, there does seem to be some subtle stuff going on but, overall, it appears, at least to me, to be a decent lens.


Do you get sharp images, both stellar & planetary? If so, be happy!


July 16, 2007 05:24 AM Forum: Astro-Physics

Rainbow in my objective?

Posted By Jeff Blazey


Of course if you are still concerned, I'll gladly relieve you of the "problem" for a fair price. wink


August 1, 2007 04:59 AM Forum: Equipment Talk

Rich field scopes - nobody consider Newtonians?

Posted By Jeff Blazey

Here's something to consider...a MN56 Mak-Newt. It's highly corrected but does have a rather small 100% illuminated field. For a larger 100% illuminated field there is also the MN55. Astounding wide field views plus they excell at high power.


August 2, 2007 11:40 AM Forum: Maksutovs

Anyone with experience on the Intes Micro M500D

Posted By Jeff Blazey


I too have the little M500 and the TEC 6. In side by side comparisons the only real optical difference was due to aperture. My particular TEC 6 has the "cleanest" star test I've yet run across but the M500 was no slouch in that regard.

In a side by side test with my AR5 w/chromacor, the AR5 was ever so slightly sharper but the M500 was better color corrected, especially off-axis and DYNAMITE with a binoviewer.

I can highly recommend one even at its list price.


September 21, 2007 07:06 AM Forum: Equipment Talk

APO vs. Achromat Focal Length

Posted By Jeff Blazey


A good rule of thumb I use for subjective color is to scale the focal ratio with the aperture. For an achromat example, my 4" F10 Jaegers gave me the same subjective false color content of my 6" F15 lens. Of course, the 4" scope is less than half the length and 1/3rd the weight of the larger.