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Jupiter (clearer) Nov 5th 2023 w/Mewlon 180c

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Posts Made By: Larry Stange

November 14, 2002 09:34 AM Forum: Film Astrophotography - Imaging and Processing

November 14, 2002 06:26 PM Forum: Film Astrophotography - Imaging and Processing

Part III and question to Herb on his work.

Posted By Larry Stange

Part III (a failed attempt to post images & language) was meant to show any camera can be mounted afocal including the really weird digital cameras with threaded mtg. hole far off of camera center & focal axis. The refractor has absolutely no vibration other than the basic vibration in the mfg's mounting of the whole scope. Images of Digital camera were improved even under my adverse conditions.

2nd question to Herb, -having been many times, and lived briefly in Prescott, Arizona, I consider it to be the finest 360 degree viewing location in North America at 1 mile high. Are you actively engaged in Astroid detection?...Southern hemisphere maybe?....(the unexplored regions) and source of the K-T event of recent years?. I would be....given funds & that location. :-) -Larry

November 16, 2002 09:22 AM Forum: Film Astrophotography - Imaging and Processing

Pro help needed on Jupitor image resolution.

Posted By Larry Stange

Given I have not yet found perfect focus, and given the heat shimmering is impossible out my OPEN window.....what could I do right now to the telescope in the way of filters, or?, to get better detail out of these typical "Adobe PhotoDeluxe Home Edition" blown up images that just came out of my afocal mtd. digital camera?.

November 16, 2002 07:14 PM Forum: Film Astrophotography - Imaging and Processing

Result of Wayne-Richard "using digital"

Posted By Larry Stange

Recieved an answer from Richard "within MINUTES" regarding the use of generic digital cameras on telescopes with afocal mounting.....In summary, we're trying to push the corpse of a dead horse across the finish line at a race track. :-(

November 16, 2002 08:20 PM Forum: Film Astrophotography - Imaging and Processing

More good info from Richard for us...

Posted By Larry Stange

This repy was a result of confirming with Richard whether my wifes 35mm DIGITAL camera (Minolta Freedom Zoom 90) would also be eliminated as undesireable for afocal use. Richards comments can keep us(me) newbee's from making costly mistakes out of ignorance. Am also investigating his Hartmann mask reference(for personal knowledge) which tho interesting and worth building to see what it does, will not really solve my basic dead horse problem.

November 16, 2002 11:06 PM Forum: Film Astrophotography - Imaging and Processing

Hartmann mask from black picture backing.

Posted By Larry Stange

2 hole focusing version works great even in daylight!. It was cut to fit snug at bottom of dew shield but not touching lens cell or lens and is extracted with two fingers into the holes quickly. In the process discovered that a barlow BEFORE a diagonal magnifies an image hugely!. AFTER the diagonal it is just a standard barlow(2X). This must mean a variable barlow can be made simply by adding different length couplers or an adjustable telescoping coupler between ocular and barlow. 'Aint science fun?.

November 18, 2002 06:19 AM Forum: Film Astrophotography - Imaging and Processing

Pre-photos w/mask at target sets up scope focus.

Posted By Larry Stange

Eye limitations & course focusers prevent perfect focus even using Hartmann mask. I believe taking a few shots thru the mask FIRST at the target would enable better focus adjustments before the final photographs. Example shown is an error in focus that I was not aware of when setting focus using Hartmann mask and my eye. I thought I had it close enough....I was wrong and the photos show it. (this is the dead horse project still.) -Larry

November 18, 2002 11:42 PM Forum: Film Astrophotography - Imaging and Processing

Thankyou Paul! was only aware of 20% of that!.

Posted By Larry Stange

You have opened new area's of research reading(and subsequent manufacturing of more masks!). I did put the cutout circles EXACTLY at the furthermost edge of aperature sides using dial verniers to measure dew shields minimum inside diameter and subtracted the OT & cell diameter so that holes just "touched" edge of aperature. I noted the "triangle" and dual "slot" language on the improved mask web sites but thought it was restricted to CCD systems. Must now go back square one and reread all those Hartmann sites. :-) I certainly appreciate your knowledge sharing on diameter of holes etc. & will RE-READ YOUR INFO MANY TIMES to make sure all you have said has penetrated!. I work with limited frontal lobe volume due to age & having performed self-lobotomy too many times.... :-) Thankyou again Paul. -Larry

November 19, 2002 12:44 AM Forum: Film Astrophotography - Imaging and Processing

Addendum to Paul....

Posted By Larry Stange

Before thorough reviewing of your data and internet research it has occured to me, (armed with your enlightened statements), if I can select a star magnitude and mask hole diameter appropriate for my particular focal ratio and ocular....it might be possible to use Hartmann technology to acquire diffraction rings from each hole or at worse....diffraction rings at critical focus to achieve a "super state" of focus from the outer rings essentially acting as a focus magnifier by their greater apparent diameter. You have stimulated dormant brain cells now and it is exciting but could be futile due to refraction at hole edges. Was able to download all 4 focusing articles of your reference in Adobe for additional reading. Tnx.-Larry

November 19, 2002 07:02 AM Forum: Film Astrophotography - Imaging and Processing

Ok, 6 hour class study period break.

Posted By Larry Stange

After wading thru 20 sites and some of their source references, I have a working understanding(I hope) of Knife edge, Ronchi screens, Hartmann variations and diffraction focusing.(the "snap" you hear is neural critical mass). Needless to say the better methods(not Hartmann) ALL require high resolution CCD camera's with focusing/pixel/intensity software OR multiple shots using blown up 35mm film on a star with a calibratable focuser. Which leaves me in a poor posture at this time. At my level, the triangle addition to Hartmann would only show me which side of focus I am on. Multiple holes without CCD & software would be useless. The converging/diverging lines by rotation would work if I can locate and mount a mickey-mouse vernier dial(electronic), or obtain a graduated helical focuser. The latter would be easiest. To go beyond my present limitations does require me to find a 35mm SLR focal plane shutter camera or be stuck forever with marginal Hartmann focusing technigues.....Sure do like those diffraction methods though!, especially the first one that was publicized....