markse68

What a great thorough comparison- thank you! I’m not in the market for a premium mount like that- my old G11 will have to do for now but i do dream of such things  Worrying that they both had issues out of the box at that price but good service is good to know

Mark

AKA ARP227- this was a stupid target to attempt from here- too low and too faint with all the light pollution (bortle 8/9) Can just about make out some shell structure with extreme stretching which is pleasing even if it is the worst astro image I've captured lol. And the longest!

~5hrs each in 10min subs LLRGBHa (composite L from all subs)

This is without any gradient removal lol

This is what it should look like courtesy of the CFHT telescope in Hawaii- pretty amazing!

https://science.nasa.gov/galaxy-ngc-474-shells-and-star-streams

oh and i missed this- Hubble imaged the core region just last year:

https://www.nasa.gov/image-feature/goddard/2022/hubble-peers-through-giant-ellipticals-layers

They think this could resemble the fate of the Milkdromeda collision in a few billion years  

Edit: just noticed how incredible this Hubble image is- full of weird and wonderful "objects". They look further away so I guess not influenced by the gravity of NGC474 but there seem to be a few interacting galaxies (?) in weird and wonderful colours just in this tiny patch of sky

Mark

I’ve never got my head around these extra curled up dimensions required for the maths of string theory etc. What is the point of a dimension that isn’t required to describe relative position in spacetime- isn’t that what a dimension is for? Or maybe these extra dimensions relate to something outside our spacetime and it just so happens that their values are always the same for everything inside spacetime so for us they are irrelevant? But then why try to describe them as curled up so small we can’t detect them? Or are they just a mathematical construct like imaginary numbers- essential for the maths but not actually “real”?

According to Wicki- “The concept of dimension is not restricted to physical objects. High-dimensional spacesfrequently occur in mathematics and the sciences. They may be Euclidean spaces or more general parameter spaces or configuration spaces such as in Lagrangian or Hamiltonian mechanics; these are abstract spaces, independent of the physical space in which we live.”

Mark

10mm BCO. You don’t have any orthos. Everyone should have a 10mm BCO Cheap too, especially sh. 

Mark

Their website is pretty bad- no idea who is speaking when in the conferences

Been having a google and found that in the year of 1896 Mars was 17" at opposition and of very favourable altitude- just like today!

1896 was right in the middle of all the Lowell Mars canals "discoveries" so an interesting time at the forefront of planetary observational science. The observation reports are fascinating

https://www.jstor.org/stable/40670965?seq=1#metadata_info_tab_contents

Lowell:

https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1900AnLow...2..205L&db_key=AST&page_ind=0&data_type=GIF&type=SCREEN_VIEW&classic=YES

BAA Mars Section 1896

https://britastro.org/wp-content/plugins/baa-frontend-tweaks/baa-check-file.php?filename=sites/1896 Final Report.pdf

Lots of talk of canals 😄. 

Interesting section on "Projections from the limb" which I noticed in images and at the eyepiece above the N polar cap- a distinct bulge in the outline of the disk!

Also they make an interesting comment about the ideal optimal telescope for Mars (presumably at 17" disk size  )- it should be 9.25" aperture- no more and no less! haha! 

These facts should be borne in mind by planetary observers!

Mark

5 hours ago, mikeDnight said:

That's fantastic Mark! Thank you for taking the time to do a little research and post it here.  It's true that Fauth was a real character. The book EPIC MOON, by William Sheehan & Thomas Dobbins, sheds more light on Fauth's life and work. He'd work all day as a school teacher, then take a significant train journey before trekking miles across country to reach his observatory, where he would spend the night observing the Moon. Amazing stamina! I sometimes look out of my house at my observatory, which is just a few strides away, and think "Not tonight". What a contrast!

Haha- I guess if you had a 15" cutting edge scope in an observatory like that and were at the forefront of observational discovery then you might be more inclined to give up some sleep

I did a bit more digging and found this interesting piece by Leo Brenner (real name Spiridon Gopčević) in the BAA Vol VI journal form 1896. He had a visit from Fauth and writes this astonishing comment:

https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1896JBAA....6..384B&db_key=AST&page_ind=0&data_type=GIF&type=SCREEN_VIEW&classic=YES

Brenner was using a Reinfelder & Hertel 7" f15 refractor https://www.istrianet.org/istria/astronomy/observatories/losinj1.htm whereas Fauth had a Merz 15" Schupmann "medial" telescope (https://stellafane.org/history/modern/ludwig.html) (https://www.telescope-optics.net/schupmann_medial_telescope.htm) yet Fauth had never seen any dark features on Mars! Mars was a similar size that year to this- 17" at opposition, though only 5.5" at time of observation. Thing I don't get is I can easily make out dark albedo markings with my little 150mm f5 reflector! Maybe it just hadn't been so elevated in those years. I really really want to get another look at Mars through the ROG 28" Great Equatorial while it's so high- last time we looked it was too early and too low...

(I stumbled across another interesting article from Brenner in the same BAA journal where he had visited Lowell at his observatory and makes some quite telling (I think) observations about Lowells eye sight- could help explain the canals!) https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1896JBAA....6..266B&db_key=AST&page_ind=0&data_type=GIF&type=SCREEN_VIEW&classic=YES)

Anyway sorry this is the wrong section for this stuff really but I do love reading those old observing reports from that era, and you started me off on one haha!

Mark

On 29/12/2022 at 11:55, mikeDnight said:

 I recieved an old book through the post this morning. Fauth's THE MOON. It's not of much scientific interest, but i love the history of lunar study, and of course the drawings made by these great observers of the past.

 

Love his drawing style and that observatory above the trees is amazing! Had a quick google and unfortunately it no longer exists  

He’s an interesting character isn’t he- had some mad ideas about cosmology!

Found this funny letter from him to “Yerkes Observatory nr Chicago” about exchanging images of the moon  

Mark

http://krbrasch.blogspot.com/2012/06/philipp-fauth.html?m=1

Wow- really amazing work @Cooking Blight! Quite beautiful too! Can’t tell from your pics how long the fins are on the heat sink/front housing- do they continue down inside the housing? Would increasing their surface area help with the cooling?

Mark

That would have really messed things up! Shame it ruined your evening  Would have made for an interesting star test! Last night I was following Sirius for a good while in my now usual hunt for the pup. Suddenly i noticed an extra diffraction spike- it looked like a JWST image- what was wrong?? I racked focus and the star test diffraction image was a D shape instead of the usual neat circles 🤔Looking up I realised I had tracked the star up to one of the mobile network antennae on the roof I observe from and must have caught it at the point where half of my aperture could see Sirius but half couldn’t. Haha! Time to move the scope! Didn’t see the pup though- maybe next time 🤞

Mark

Nice! I’ve tried Mire de Collimation but not Al’s. The slightly awkward thing with Mire is resizing the circles which you can only seem to do by dragging the window bigger- having a numerical scaling feature looks like a big improvement. Like the Ocal tool- neat! If only you could adjust focus of the camera too  This should be great with a guide cam or webcam though- I’ll give it a go.

(small typo- should be thickness)

Mark

Was going a bit stir crazy- great to be back out again tonight. Mars was looking so great in the 150p that it seemed sensible to swap to the 200k and it’s true you know- aperture is king  It’s just easier to see things with the 8”- the same things just bigger and clearer.

I really do need a taller tripod though- on my knees with a crick in my neck from the straight through finder.

Mark

Missed Venus and Mercury by about 30mins  But took a tour of the others just for the heck of it  Mars is looking great again tonight!

Mark

12 minutes ago, ollypenrice said:

Talking about extremes, a friend about 20 miles away uses a 31mm Nagler for planetary observing. 

Haha yea we were using a 24mm for ~ 355x on Mars in the Great Equatorial at the ROG last month 😂

Eyepieces are very addictive- and luckily don’t take up much space to store They’re all different and having a few on hand to attempt to get the optimum magnification/contrast on a target is all part of the fun

Been using a fine zoom ep for a while and enjoying the simplicity of the setup but going back to well populated fixed eps was very satisfying too.

When i get a new ep, even though it probably wasn’t necessary, I’m always itching to get out and try it and that usually leads to a spurt of enthusiasm that lasts far longer- a good thing i think  

Oh and never get rid of any- you never know when that’s the one that would really be perfect for your target/conditions 🤣

Mark

9 hours ago, Ratlet said:

M48 extension tubes and some metric Allen bolts. 

proper christmas pressies 🤣

What didn’t I see- the pup  The seeing was so steady- fantastic sharp view of Jupiter earlier in the evening and Mars was great too, Sirius was actually quite steady and I was sure the pup would reveal itself. But after repeated long attempts I had to give up- freezing cold despite it being only about 10deg  (but high humidity). There were fleeting moments when i kidded myself that a speck had flashed into existence but nothing concrete. Next time…

Mark

They look great! One question though- you’re getting really nice detail and definition on the low contrast dark markings but the disk edge is blurry? It’s the other way round for me- the disk is sharp and the details are too but low in contrast and take concentrated observing to piece them together into a whole

Mark

Should be wrapping pressies but the sky is clear and the seeing is really great- had a lovely clear view of Jupiter earlier and Mars is revealing a lot of detail. The Tal 100r can’t compete with the 150p but Mars polar cloud/cap was more visible with it 🤷‍♂️ Contrast I guess 

Mark

That’s awesome! Does it really weigh only 8kg? Are you running the Azimuth drive belt around the bike wheel and the motor travels with the seat? Have you got a video of it in operation? Great work Mr H!

Mark

Has nobody got one yet? They’re out in America…

They have satin barrels like the XFs, and Don likes them

Mark

If you search for moon and sky glow filter on ebay you can find some cheap generic filters “equivalent” to Baader Neodymium if you can’t find one of them. Maybe worth a try for a few quid. There’s not much difference apparently https://www.cloudynights.com/topic/533147-spectroscopic-analysis-comparison-of-planetary-filters/

Mark

Looks great Joe- they did a really nice job on that adapter with the engraving and all! Interested to know how much of a weight saving this has made if any? That SW focuser seems pretty hefty

Mark

But if they return to original form it’s elastic surely? I can imagine a similar thing happens when 2 snooker balls collide or 2 ball bearings in a Newtons cradle (on a much smaller scale obviously)

I understand your point about the water wheel Jim - of course if the ejecta had been ejected sideways instead of backward they wouldn’t have contributed to the momentum transfer and maybe that is what the scientists were surprised by, i’m wondering though if the ejecta caused a greater deflection than had it been a perfectly elastic collision (a ridiculous hypothetical i realise) and how much the elastic deformation analogous to the golf ball affects this?

Mark

Thanks Steve, and get well soon!

Mark

Yes I think that would be good although knowing the physical dimension isn’t very useful? Maybe just the “Effective fs diameter” like Televue do would be all that was needed? Where did you get those values you listed from though? they don’t seem to correspond to the physical mfrs dimension- did you calculate them from something?

Mark