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M 33

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Posts Made By: Randy Roy

November 3, 2006 05:34 AM Forum: Equipment Talk

Is it me or my equipment

Posted By Randy Roy
Generally, I believe most optics (even SCTs) today are pretty good for visual use. I have a TOA130 with exquisite optics, but for visual use I am quite please with my <$1,0000 12" dob. I love the high contrast, wide flat fields of the TOA, but its best advantages are only tested using CCD or film.

I had truly fantastic views of M33, the Helix nebula and the Veil with my cheapo dob a few days before the last new moon from our club's dark site. Seeing was steady, my scope was cooled down and the collimation was dead on. For me the trick for great visual viewing lies more in aperture, dark skies and seeing than in expensive optics.

November 9, 2006 02:24 AM Forum: Eyepieces

Effectiveness of Televue eyepieces with long f/l t

Posted By Randy Roy
I would agree with your logic, somewhat at F10 and higher. SCTs and Maks are very forgiving of eyepieces and many of the low-medium power eyepieces that do not work so well at say F5 and below, work quite well at F10. Well executed plossls (e.g., TV) work great at F10 and above and that would be my ep of choice for an SCT or Mak. But my F5 dob loves the Pans and T6's.


November 21, 2006 05:50 PM Forum: Equipment Talk

Trying again (no help here) Diagonal quality ??

Posted By Randy Roy
John,

I just received a 2" Astro-Tech dielectric diagonal for refractors and am very pleased. I have had all the rest over the years and the Astro-Tech is very well made. It looks like a WO and is made from a single piece of aluminum. Both the 2" ep port and 1.25" ep adapter use a brass compression ring.

I believe the enhanced mirror version is the same build quality (again, the same as the WO). I bought the dielectric version simply because the coatings are more rugged and can be cleaned more easily.


January 8, 2007 03:39 AM Forum: Deep Sky Observing

A comfortable split?

Posted By Randy Roy
How true. I find I can split just about anything at anytime if I wish hard enough. To misquote Einstein "When it comes to close splits, imagination is more important than knowledge." smile

On really difficult splits, like Sirius and the Pup, it helps to superhydrate on coffee while meditating on CCD images taken of the double. The same goes for extremely low surface brightness DSOs. This method often works, even when the skies are cloudy.

But seriously, I chuckle when I see postings like, "I'm not sure, but I think I split Sirius last night." If you are not sure, you did not split it.

January 8, 2007 03:48 AM Forum: Reflectors

Downsizing Why and What

Posted By Randy Roy
Bill,

I sold my 16" Starmaster a few months ago, after three years of getting great views. It had goto and track and all the other bells and whistles.

I replaced it with a new 10" Starmaster Hybrid. Why? The hybrid breaks down into two parts and is very easy to transport to our clubs dark site. It doesn't have quite the reach of the 16", but I believe there is not a 10" reflector anywhere that gives better views. I miss the goto and track for high power planetary observing, but the DSCs are just so easy and light. I never concern myself with charging batteries and am always ready to toss the scope in the back of the Jeep and go.

At home, I actually use a CPC9.25 that I roll around on wheeley bars. I have decided for me, about 10" is enough aperture to satisfy my observing needs.

I know it's not for everyone, though.

January 20, 2007 12:29 AM Forum: Eyepieces

27 televue through a barlow?

Posted By Randy Roy
Yes, you can barlow the 27 Pan with great results. You will need the Panoptic barlow interface, however.

http://www.buytelescopes.com/product.asp?t=55&pid=1082&m=3


January 28, 2007 12:57 AM Forum: Equipment Talk

Is GOTO worth it?

Posted By Randy Roy
Well, I would rather have a G11 without goto for a 10" SCT than a GM8 with goto for the same OTA. But all else equal, goto simply gives you more options. I love to push my Starmaster without goto and have a lot of fun starhopping at our club's darksite. I especially like using Telrad charts to find the faint fuzzies. But, at my home in suburbia or at public events when it is common to have 20-30 people waiting in line, I much prefer to bring out my goto Celestron SCT.

Different strokes . . . I like both.


January 31, 2007 02:00 AM Forum: Reflectors

Aperture vs. Limiting magnitude

Posted By Randy Roy
Great question and the answer is yes. Here is the math.

The 10" dob has a magnitude gain of 7.8 mags above the dark adapted human eye (e.g.7mm).

The equation is 5*Log10 (D1/D0) where D1 is the aperture of the scope and D0 in the entrance pupil of the eye.

For a 10" scope you would have
5*Log 10 (250mm/7mm)=7.8 mags

For a 25" scope you would have
5*Log 10 (635mm/7mm)=9.8 mags

With Mag 4.5 skies, the 10" would let you see stars about at about mag 12.3 and the 25" would allow you to see stars at about mag 14.3

With Mag 6.5 skies the 10" would let you see stars about mag 14.3 and for the 25" about 16.3.

A short cut would be to determine the mag difference in the 25" and 10" apertures for all visual limiting magnitudes:

5*Log10 (25"/10")=1.99

This means the 25" will let you see about 1.99 mags deeper than the 10" for all visual limiting magnitudes.



February 1, 2007 11:25 PM Forum: Reflectors

Obsession/Starmaster comparaison

Posted By Randy Roy
I now own my third Starmaster scope and I like everything about it. Several years ago, when I purchased my first new Starmaster, I asked Rick Singmaster why I should buy a Starmaster and he quickly said, "the Zambuto mirror". It is not that others do not make great mirrors, too. It is just that if Carl Zambuto makes the mirror, you know it will be superb. Actually, I like the Starmaster structure, too. It has an industrial strength look and feel that appeals to me.

The Obsession scopes are beautiful and I am sure I would be just as happy with it. They do have a sort of furniture like appearance about them, though I would rate them just below Starmaster in every other dimension. I would love to have a premium dob with Feathertouch focuser, Starmaster's wiffle-tree mirror cell, Zambuto primary, Rick Singmaster's support and Obsession's sexy lines and that cool little brass plate.




February 10, 2007 02:28 AM Forum: Reflectors

portaball/lightbridge?

Posted By Randy Roy
Buy the 12" Lightbridge and enjoy it while you are saving your money for the 12.5" Portaball (for however long that takes), then sell the Lightbridge!

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