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Questar Observing Reports (Post yours here)

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#1 Optics Patent

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Posted 14 October 2019 - 11:59 AM

My report doesn't deserve a whole thread, so I thought I'd offer this thread for other observation reports that are also worth sharing but not deserving of a new thread.  This is a fine place to comment on weather and conditions as well.

I had a much anticipated session with the Seven and the full aperture Questar solar filter I acquired earlier this year.  Texas summer heat was enough to demotivate me to stand out in the sun until fall finally arrived, with a crisp 70-degree day with clear blue skies and a gentle breeze yesterday.

 

With a 16mm Brandon, the field of view (without Barlow) was maybe less than a solar diameter.

 

Unlike an impressive recent lunar observation with striking texture on a smooth maria at the terminator, the solar disc was unimpressive and virtually featureless.  Plenty of mirage from the air movement seen at the limb, and a slight brightness fall-off at the limb, but no texture or spots.

 

Ho hum.  The brightness with the "salad plate" filter was comfortable (unlike the finder view that was on the bright side but not uncomfortable for brief periods).

 

Cloudy today. 

 

PS:  I encourage an astrophotographer to start a "Questar Astrophotography Images (Post yours here)" thread to consolidate all the wonderful images in one great thread.


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#2 Gregory Gross

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Posted 14 October 2019 - 03:31 PM

Unlike an impressive recent lunar observation with striking texture on a smooth maria at the terminator, the solar disc was unimpressive and virtually featureless.  Plenty of mirage from the air movement seen at the limb, and a slight brightness fall-off at the limb, but no texture or spots.
 
Ho hum.  The brightness with the "salad plate" filter was comfortable (unlike the finder view that was on the bright side but not uncomfortable for brief periods).

It sounds like the seeing wasn't too great when you observed the Sun in your Q7. What time of day were you out? I find that mid-morning hours before the heat of the Sun really starts to churn up the atmosphere is the best time for solar observing. I feel like I've gotten out too late with my solar gear when the clock ticks past 11 am or so.

 

Much to my surprise, a few people have reported on the thread "How Do You Use Your Questar?" that they've observed photospheric granulation with full-aperture solar filters attached to their 3.5" Qs. I would imagine that a 7-inch Q is going to exaggerate the effects that poor seeing has on bluring out any granulation one might be able to see. The next time you're out for a solar observing session, it would be very interesting to do a side-by-side comparison of the performance of your Q7 with a Q3.5 fitted with a full-aperture solar filter. Maybe the smaller scope will perform better?

 

Incidentally, that "slight brightness fall-off at the limb" is a phenomena called limb darkening. Essentially, photospheric gas is cooler, less dense, and less opaque at higher altitudes than it is further down. At the limb, we're seeing that gas only at a higher level, so it emits less light and appears darker. At the center of the disk, however, one is looking down into a deeper, hotter, more dense, and more opaque layer of the photosphere. I think it's really neat to see that effect. It's a reminder that the Sun is not a solid ball of matter but rather is a huge seething sphere of hydrogen.


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#3 Gregory Gross

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Posted 14 October 2019 - 04:32 PM

I was out with my '62 Questar this past Saturday night taking advantage of the clear weather we've been having. I'm finding more and more that my Questar wins out as the scope of choice during those nights when the weather is beautiful and the Moon is up for viewing.

 

This is the Questar forum, right? Let me gush a bit about my Q: I had no problems snapping all of the lunar features into sharp focus. I just knew I had nailed focus even in spite of the teeny tiny small focus knob. Very little if any mirror flop. I find that 90mm of aperture is just right for full-disk lunar observing and that the 40x eyepiece fits the Moon comfortably in what I roughly estimate to be its one-degree true field of view. My failed coatings even help to step down the brightness somewhat, making for a more comfortable observing experience.

 

Attached is a snap shot I took last Saturday with a Canon point-and-shoot camera aimed into the eyepiece.

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