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M20 Trifid Nebula in LRGBHa

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Posts Made By: Mike Ratcliff

March 14, 2009 07:02 PM Forum: Eyepieces

Nagler 11mm Type 1 vs. the New Type 6

Posted By Mike Ratcliff
Just a friendly note, in case you didn't know. The 11mm T1 Nagler is a collector's item now. Typically goes for much more than any other T1, as in double the price at least.

Or you can donate them to me and I'll take care of them. wink

Mike

May 3, 2009 05:51 PM Forum: Eyepieces

Powermate AFOV

Posted By Mike Ratcliff
Paulo Mesquita said:

This might e a stupid question but I can't find any info on this and since I'm a newbie...

f I use a 2" x2 Powermate, for example on a 17mm Ethos, will I have the same AFOV (100º)? or will the AFOV be narrower? My doubt is because if there is a 8mm Ethos with 100º of AFOV then one could assume that a 8,5mm "virtual"EP generated from a 17mm Ethos + a 2x Powermate would also give a 100º AFOV.

Am I wrong about this?

Cheers

Paulo,

A barlow or powermate would keep the AFOV usually. So the answer is yes, the 17mm + powermate would be similar to an 8.5mm Ethos, but with more glass and weight. The performance may not be quite as good as an 8.5mm. And switching barlows is not as convenient. But a barlow or powermate is a good way to save some money.

There are some barlow/eyepiece combinations that don't work well. For example, the Televue plossls and the Televue 1.25" 2x barlow would cut off some of the AFOV, from 50 degrees to about 45 degrees.

I don't know if the Ethos will have a similar problem. You may need to ask someone who has tried it.

Hope that helps.

Mike

May 29, 2009 10:58 PM Forum: Eyepieces

36mm Hyperion Aspheric vs 36mm Siebert Observatory

Posted By Mike Ratcliff
Well, I owned a 34mm Siebert Observatory for a while, using with a 16" f 4.9. There was definite astigmatism in the outer areas, say 20%. I would not believe Mr. Siebert's statement to be totally correct about no distortion at f/5.2, unless he is referring to lack of pincushion.

Pincushion would show as bent lines in daytime, or as stars seeming to follow curved lines while you move the view around. Pincushion can cause a little bit of nausea like seasickness if you pan around too fast.

The Televue Panoptic, which is more expensive, supposedly trades low astigmatism for higher pincushion, from what I have read. I think the Siebert Obs goes the opposite way and has low pincushion.

If it were me, I would take the low astigmatism and get better stars when the telescope is not moving. I think you will detect some astigmatism from the Siebert, which is normal for less expensive eyepieces in fast scopes.

The Baader I do not have experience with.

Hope that helps.

Mike

June 23, 2009 06:24 PM Forum: Deep Sky Observing

NGC 5053

Posted By Mike Ratcliff
Yes, I've seen 5053 in both a 6" and 16", but only in dark skies.

It is considered a challenge object with a dim surface brightness. In fact it is on RASC's (Canada) official list of Challenge Objects. So almost any light pollution would really hurt. In the 16" I was first able to see the some scattered individual stars before seeing the background glow. It is much different than regular globular clusters that have a brighter core. 5053 is almost like someone stole the core, which was my first thought upon finding it.

You probably did see it but may need another observation to confirm. And you could also sketch some surrounding stars and compare the pattern to some photos, such as the DSS surveys.

Mike

August 29, 2009 06:05 PM Forum: Reflectors

New record set

Posted By Mike Ratcliff
Ed,

Beautiful but I have a bad neck and could not handle that downward eyepiece position. Could a diagonal be added?

Mike

September 26, 2009 07:43 PM Forum: Eyepieces

Not your usual XW20 vs 24 Pan Optic Comparison

Posted By Mike Ratcliff
The big overhanging eye cup of the XW will definitely reduce the infrared heat loss to the sky and slow down dewing.

Moving to S. California or Arizona is your best course of action. wink

Mike

January 27, 2010 04:14 AM Forum: Ask rating questions here

Why are my 5 star ratings disappearing??

Posted By Mike Ratcliff
John, Probably because some of your ratings were from people who have recently left AM, most likely involuntarily. Same with gaps in forum threads you see now and then. Your 612 5-star ratings are still in the respectable category, wink (amazing actually).

Mike

July 12, 2010 06:32 PM Forum: After Dark

Zooland at Pinos

Posted By Mike Ratcliff
I usually observe farther east like Joshua Tree or near Barstow. But I almost went to Mt Pinos -- for the first time -- based on the more favorable clear sky clock forecast. Also to meet some of you guys and see what the conditions are like.

But at the last minute I went instead to the Barstow-Baker area. It was clear between 11pm and 2am, so it worked out.

Based on what you said, I had better get there early!

At Joshua Tree it is almost guaranteed that I'll attract a small group of neighboring campers to look through the dob, and it is usually enjoyable. On occasion some really excited people who might later get into the hobby.

Mike

July 23, 2010 03:34 PM Forum: Equipment Talk

O-III and a dark sky site

Posted By Mike Ratcliff
Jeff,

No actually the OIII filter and other nebula filters are still very useful at a dark site. Essential equipment really. "Don't leave home without them". Even at the best dark site in the world, there is enough sky glow to interfere with nebula views. The sky is never truly dark like a cave. And of course most dark sites aren't pristine anyway.

Mike

July 23, 2010 07:56 PM Forum: Solar System Observing

Oh Boy! Mars as big as the full moon time again!

Posted By Mike Ratcliff
To my mother-in-law's credit, this year she asked me if this were true before sending it on to her friends.

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