16 replies to this topic

[David Gray]

From the last two nights with widespread cloud on both – especially last night. The 27th had started off with that racing watery-looking turbulence over Jupiter and Saturn......lots of detail but too mobile for useful rendering.  By time I got to Mars and not a lot higher than Jupiter/Saturn things had settled markedly.  Looking at the scattered cloud (and a halo round the Moon) I went for the sketch with Mars at 18º degrees high.  Which had me hoping for better on the 28th – indeed it was but the week long forecast for a long clear night was wrong, wrong, wrong.....again........!

 

In fact last night was looking a lost cause:  a good clear span along the north: the Plough to Perseus had me hoping.  Then a tongue of clear branched off southward and brought Mars into view. But that was with the CM ~265º of the previous night’s sketch albeit the seeing looking better but all too brief anyway for a second rendering.

 

Even so that steadier seeing last night had me hanging on especially as the Satellite Imagery was indicating clearer  conditions creeping in from the west.  Creeping was right, and only kept vigilance when spotting slightly breaking cloud in the s’west showing moonlit edges with the Moon – due south – peeking through at times.  The cloud, breaking more as it very slowly went, finally a very detailed steady view got me last night’s sketch......then more cloud.

 

Phase only 99% now and the  bluish haze getting more apparent terminator side; with the limb-side haze seeming to tend to a slightly more violet hue than previous.

 

The rosiness in the deserts around Syrtis Major perhaps the most striking to me so far this apparition........Dave.

 

Edited by David Gray, 30 September 2020 - 08:50 AM.

[niteskystargazer]

David,

 

Very nice sketches of Mars: Syrtis Major  .

 

CS,KLU,

 

 ,

 

Tom

[frank5817]

David,

 

Beautiful sketches of Mars with stunning detail.

 

Frank

[David Gray]

Many Thanks Tom, Frank and you Nine Likers.......

 

Next good clear night (tomorrow......they say.......), I’ll get

the old/1961 3-inch onto it; also with the 10-40mm iris diaphragm

if clear enough.

 

Cheers
Dave.

[sunnyday]

great talent, looks like pictures, thanks.

[flt158]

Stunningly good sketch from you, David!

 

Syrtis Major looks extremely good.

Delightfully small South Polar Cap too.  

I'm just noticing that Hellas is not as bright in 2020 than it was a number years ago. 

Is there any particular reason for that?

I did observe Mars last Friday night 25th September and Hellas was faint then also although my sky conditions were poor at the time. 

I could use a mere 112X on the red planet.  

 

Clear skies from Aubrey.  

[David Gray]

Many Thanks Sunnyday, Aubrey....

 

Aubrey........Hellas I think it the wrong Martian season for that to be bright.....and possibly some aftermath of last apparition's dust storm.  Come the colder seasons on Mars the basin is often filled with bright cloud.  That many times has fooled the unwary into thinking it was the SPC......!!

 

On the Linked Post you asked........(pardon my oversight. ...)

 

”635X on Mars is truly amazing.  Can you tell us what eyepiece gives you that magnification, please?”  https://www.cloudyni...ion/?p=10527552

 

Those EPs are Meade 12mm HD-60s; these rival my old Zeiss Orthos, and of course I have a pair of the Meades for binoviewing.  What I further like with those is they work well with the 0.5x focal reducers (Antares). 

 

That combo giving 515x which I particularly like for double star work as against the reducers' pairing with all other EPs I have....for some reason the HD-60s have a great optical compatibility with those reducers.  The only thing with those HDs is I’m not overly keen on those rubber eyecups.

 

It should be noted that all given magnifications in my posts are as determined by exit pupil measuring (Optical Micrometer - +/- 0.05mm) and the average of a good few measures is rounded to the nearest 5x. 

 

Note that with the resultant 515x the reducers are giving nowhere near half of 635x; I reckon that is down to the spacing entailed by the barrel length of the HDs.  Also always higher with my regular Meade 20mm 5000 Plossls where I get 385x and with reducers 285x (some image degrading/softening with those) again due to EP architecture I guess..........But it is all fine and productive..........

 

With the D-K’s f/16-f/18 (6640mm to >7000m fl) it is dependent on the position/secondary-distance of the primary to accommodate the Amici Prism, BinoVu, ADC etc. what the final magnification will be.  Thus those 12mm HD-60s can range from 550x to 640x....so nice comfortably large EPs for high powers......but those H-D60 rubber eyecups I will have to modify/replace asap (I keep saying)......!

 

Pardon the long-winded explaining..........

 

Cheers,
Dave.

Edited by David Gray, 30 September 2020 - 01:37 PM.

[flt158]

Many Thanks Sunnyday, Aubrey....

 

Aubrey........Hellas I think it the wrong Martian season for that to be bright.....and possibly some aftermath of last apparition's dust storm.  Come the colder seasons on Mars the basin is often filled with bright cloud.  That many times has fooled the unwary into thinking it was the SPC......!!

 

On the Linked Post you asked........(pardon my oversight. ...)

 

”635X on Mars is truly amazing.  Can you tell us what eyepiece gives you that magnification, please?”  https://www.cloudyni...ion/?p=10527552

 

Those EPs are Meade 12mm HD-60s; these rival my old Zeiss Orthos, and of course I have a pair of the Meades for binoviewing.  What I further like with those is they work well with the 0.5x focal reducers (Antares). 

 

That combo giving 515x which I particularly like for double star work as against the reducers' pairing with all other EPs I have....for some reason the HD-60s have a great optical compatibility with those reducers.  The only thing with those HDs is I’m not overly keen on those rubber eyecups.

 

It should be noted that all given magnifications in my posts are as determined by exit pupil measuring (Optical Micrometer - +/- 0.05mm) and the average of a good few measures is rounded to the nearest 5x. 

 

Note that with the resultant 515x the reducers are giving nowhere near half of 635x; I reckon that is down to the spacing entailed by the barrel length of the HDs.  Also always higher with my regular Meade 20mm 5000 Plossls where I get 385x and with reducers 285x (some image degrading/softening with those) again due to EP architecture I guess..........But it is all fine and productive..........

 

With the D-K’s f/16-f/18 (6640mm to >7000m fl) it is dependent on the position/secondary-distance of the primary to accommodate the Amici Prism, BinoVu, ADC etc. what the final magnification will be.  Thus those 12mm HD-60s can range from 550x to 640x....so nice comfortably large EPs for high powers......but those H-D60 rubber eyecups I will have to modify/replace asap (I keep saying)......!

 

Pardon the long-winded explaining..........

 

Cheers,
Dave.

Thank you for that explanation for Hellas, David. 

I am in full agreement with you. 

 

And a huge thank you for providing me and the rest of us with your eyepiece details. 

Your HD-60's are the business when conditions do occur! 

Those binoviewers must be extremely handy when you are sketching. 

 

Please keep up the great work, David. 

My Irish friend Darren (DDEV) and I are massive admirers of your work.   

We were only talking about you last Friday night (25th September) with great appraisal. 

 

Clear skies, 

 

Aubrey.

[Uwe Pilz]

Incredible.

[Redbetter]

Beautiful.  Wish I could record detail like that in my sketches...it is there on the better nights, but I can't do it justice.  I've been working nearly the other side in recent nights, with unusually good seeing for the backyard in early fall.  My old #25 filter (a bright one, midway between my newer AT #25 and #23) has been my go to for improving contrast and cutting through the seeing, but at times I have actually had a few minutes of steady skies at ~400x unfiltered with the 20".   I should probably go back and try to make a composite of what I have observed. I am not getting those "spaceship porthole views" but there are moments when things are  steady for a second or two, and small details in Valles Marineris snap into view.  

 

The closest I have seen that captures what I see, but am not getting down properly in my sketching, is this image from 9/29 UTC by Kevin Thurman.   Link.  Visually compared to the image, with the #25 the planet is considerably brighter and reddish orange.  The contrast in the dark regions is slightly weaker particularly to the south.  Without a filter the NPH is more apparent and bluish.  Trying to accentuate any clouds or blue through smokey skies and with an 80A is bleeding too much yellow/orange through, so I employed a #38A.  With the latter the planet was electric blue/almost violet with a thin bright "rind" of cloud along the limb, along with the glow of the NPH.    

[David Gray]

Thanks Aubrey (my regards to Darren/DDEV), Uwe,  Redbetter.......

 

Redbetter: yes  there is a lot of complex detail in that region (CM ~30º).  In fact with my effort of Sep. 17 (CM 32º) I struggled to get it all faithfully placed/inserted on my regular 50mm (BAA standard) disk outline and have since gone to 65mm...I use a 64x60mm ellipse for Jupiter (BAA standard); and Saturn’s disk: 55.6x51mm (Outer Ring A 126.5mm major axis).

 

So far this apparition I have done little with filters – partly due to haze and scattered-cloud so prevailing in recent skies.........not to mention a Recycling Plant fire – 4000 tons of plastic waste - < 2 miles s’west and smouldering/smoking & stinking for weeks.....giving me a slight taste of what you guys are suffering!

 

I like the 38A; can’t say I have ever been a fan of the 80A: long-time filter-guru A.W. Heath (going on 90 and still observing – acc. recent letter!) calls it next to useless for his critical investigations. 

 

http://articles.adsa...JBAA..127..159H

 

I think some 80A application when stacked with various others that I will try with Mars; and recent years have had some good results with Venus: #15+#58+#80A – also plus the Neodymium lately.  Which stems from even earlier success with #15+#58.......  

 

http://articles.adsa...000229.000.html

 

I suspect these times there is some disparity twixt various makers......things were simpler with the albeit less durable Kodak gelatins we once used.  Heath still has a set of long-gone Dufay Chromex Tricolour; (acetate I think).  He has even experimented with various chemicals in solution for filters

 

Below shows my collection of trusted ‘modern’ types........BAS (Bedford Astronomical Supplies), no longer available, come from the same stable, I believe, as my 16.3” D-K.

Edited by David Gray, 04 October 2020 - 09:05 AM.

[Redbetter]

David,

 

I have had some good use of the #80A Orion (Japan ~1995) with my 8" SCT in prior oppositions.  It passes sufficient yellow and orange that it doesn't provide "in your face" level of contrast difference.  It is more of a blend of showing the existing geographic features with the atmospheric effects somewhat accentuated.  In some ways it serves more as confirmation of what is suspected without a filter, or is merely hinted at with a red/orange filter.   

 

I have only had the Astro-Tech (GSO most likely, or Synta?) #38A for the past two oppositions.  Haven't used it much, but am beginning to appreciate the discrimination it provides.  I might have to try it on Sirius B at some point...I am curious what it will do to A (spectral class A0) compared to B.  Hmm...it might work even better on Procyon to keep the glow of the B component while suppressing the even yellower glow of Procyon A (of F5 spectral class.)  I have never seen Procyon B...this might make it feasible, particularly if paired with an occulting bar.

 

Your image of filters is helpful.  My old Orion #25 (Japan ~1995) is a decent match for the Parks #25, while my AT 23A is about midway between your 22 and 23A.  My newer AT #25 is more of a brick color in between the 25 and 29 you show.   The AT #29 I have is even more of a deep wine red.  To my eye, neither the AT 25 or 29 have any orange hue to them, the difference between the two is primarily in brightness.  

[David Gray]

Procyon:  Jan/Feb this year I gave some intense effort seeking Procyon B and a couple of nights thought to catch it.  The doubt was the PA: the right quadrant but each time more around 330-340º than the ~316º (stelledoppie).

 

Also I spent some time with frequent views of Lambda Ori (Sep. 4.5”) to keep some feel for the Procyon AB 4.6” separation.

 

Last entry in my notes (Feb 6) using – 1st time trying – the 80A(!)+Neodymium, Pick 7-8 but some “whirligig speckles” with one rather more static and again near that 330º+ PA........Commented that the filter combo rendered Procyon A a hue similar to that of Altair; and further noted: "try the Zeiss 14mm Monocentric (485x and/or Barlowed to 840x)" Come that perfect night......!  Never caught a good enough night for that into Spring so will give it all a go again in due course.

 

Edit: I did think to check a few other bright stars for a non-moving 'whirligig'; but none apparent, so am left wondering...........

 

A rare nearer to perfect sky and I feel the 16.3” D-K has a chance.....but I want an undeniable sighting even so.......

Edited by David Gray, 06 October 2020 - 10:12 AM.

[stuart keenor]

Outstanding work david I applaud you !👏👏 Just waiting for some good seeing here in wales 🏴󠁧󠁢󠁷󠁬󠁳󠁿

[David Gray]

Thanks Stuart.......

 

Hope you got that good seeing.

 

Was a pretty good and improving sky here last night in spite of forecasters deciding it was going to

be completely cloudy after days of predicting otherwise......!

 

A couple of sketches to 'scan' (camera) then hope to post after colour-tinting later today; if some

essential diy work goes ok..........

 

Cheers,

Dave.

[dweller25]

Superb observation and drawing as usual David 

[David Gray]

Thanks David,.....

 

Cheers,

Dave