MilwaukeeLion

Inexpensive tip if mounting pc and battery to scope. Might not be pretty looking but easily adjusted to balance scope in dec. I just use 2 micro fiber car wash sponges and 2 bungees. No slippage, compressed sponges grip nicely. Have a strip of heat tape (motorcycle exhaust tape) on sponge under pc. Doesn't have a fan, gets hot doing high speed captures or sun/moon/planets. Viewing or capturing at say 1 sec exp or slower speeds is not an issue, stays warm but not hot.

Was having fun remote viewing in AC last night due to heat & mosquitos.  Where I am even with bug spray just sitting next to mount causes hundreds of mosquitos to land on scope trying to get at me.

7 hours ago, david_taurus83 said:

Excellent! Have you got any still frames?

Thanks, in the lunar imaging section.

2 hours ago, vlaiv said:

You don't get that much under sampling as you might think. Actually with 80mm scope, I don't recommend going below say 1.5"/px - 2"/px because there is no point really.

There is quite a bit of difference in optimal sampling rates of DSO AP vs planetary AP.

With lucky imaging you are used to going after critical resolution - maximum provided by aperture. You discard lesser frames and in the end you have enough SNR to do some sort of frequency restoration process - be that wavelets or deconvolution or whatever.

With DSO ap things are quite different - there is different metric that is associated with optimum sampling rate and it is FWHM of stars in your subs. Scope aperture comes into that equation, but there are other contributing factors - seeing, guiding/tracking precision and pixel blur (that one is important to some extent in planetary ap as well).

We are used to think about seeing in terms of FWHM, but most of the time, FWHM that we measure, even in short exposure like 2s FWHM where guiding/tracking error is minimized, still depends on aperture as well as seeing conditions. You will get larger FWHM with smaller scope for the same atmospheric seeing.

Actual seeing (instrument independent one) is actually better in terms of FWHM than people usually suspect. It is often in range 1-2". Local seeing can be quite different to that if there are local thermals as you undoubtedly know (scope thermals, local heat sources like concrete / asphalt pavements and roads, houses even bodies of water). These have cumulative effect in long exposure.

In any case, here are some "tips" for sampling rate when doing DSO imaging:

- On most nights with 80ED you will have about 3"-4" FWHM, not because of seeing, but because of all things combined. Different scope will have smaller FWHM than that (for example 8" reflector)

- Let's say optimum sampling rate (but things are not so clear cut here as in planetary, because we use Gaussian approximation, and gaussian shape is not band limited so we can't find critical frequency when doing such approximation - but we can find sensible cut off point) is FWHM / 1.6. For example for 3" FWHM you would need to sample at 1.875"/px, while for 4" that would need to be about 2.5"/px.

- Due to pixel blur you can in practice go as low as x2-3 that value, meaning you can go up to 4-6"/px and you won't get aliasing artifacts from under sampling. Blocky stars are sort of a myth. You can get single pixel stars if you under sample greatly, but it is up to interpolation algorithm when you "zoom in" (and in reality you should not zoom in past 1:1 - meaning one image pixel per one device pixel) how that star will look. Nearest neighbor interpolation will indeed make it look like square, but other interpolation algorithms will not (they might have other "artifacts"). After all - just look at images done with simple lens of short focal length (like samyang 135 or even 50mm lens) - no blocky stars, although aperture is comparable to 80mm (Samyang 135 is F/2 lens so aperture is 67.5mm - very close to 80mm scope).

- DSLR or any other OSC sensor will sample at twice "base" pixel size in reality - due to bayer matrix, every other pixel "counts" as sampling point for particular color, so samples are spaced not single pixel width but double of that. However pixel blur will be that of single pixel width

 

 

Good stuff, adding to your folder of critical sampling info and formula to calculate size of balloon passing in front of sun.

12 hours ago, vlaiv said:

Maybe you should use different approach given your choice of sensors?

Rather than thinking in terms of maximum resolution on a given night for particular target, you decide on target based on conditions for any given night?

ASI120mm is not really suitable for large targets unless you want to do mosaic. DSLR on the other hand is very good for wider field and larger targets. Less than optimal seeing - go for something large enough that won't suffer so much because of missing finest detail. On a good night choose to do high resolution smaller targets - like PNs or small galaxies?

Just seems counter intuitive to me being I mostly do lucky imaging / look at critical sampling and complain seeing was poor using C11.  With ED80 using same cameras with exceptional seeing you get significant under sampling vs just ok seeing which is ideal pixel size.  More excuses for poor result, can never have enough of those.

1 minute ago, maw lod qan said:

I tip my hat to you. That is incredible!

Where are you finding information showing the transit timing?

Calsky.com great site, set up your log & lat, it will send you emails on anything you want in advance of it happening.  ISS transits from your location, other bright passes from your location, moons passing Jupiter, metor showers, comets, endless upcoming space events.  You will like it guaranteed.  

Just now, Davey-T said:

That's pretty cool ML, well done, is this from your home location ? only ask because the ISS lunar transits always manage to avoid my location by miles.

Dave

Thank you Dave, yes and a second possible ISS/lunar transit coming this Sun from my yard.  Just dumb luck, kind of imaging I am best at 😀  This coming pass if not cloudy...would run along terminator line which would be very cool to capture. 

ISS passing between Apollo 11 & 17 at actual traveling speed = 27600 kph.

Capture details

7/15/2019 03:19:20 UT

ED80 - ASI 178mm - 3096x2080 - 22 fps - mono8 avi - exp .002049 - gain 52 - sharpened and gamma added - gif - in PS.

Curious if anyone chooses which camera to image with based on evening seeing?  Was looking at different camera combo resolutions paired with ED80 at ok seeing FWHM of 2-4". Seems odd that ASI120mm is better option than DSLR 4.88 um with ok seeing.  Also seems odd if seeing improved during night both become worse - significantly under sampled.  Should be rooting for poor seeing on nights I want to use my ED80 and DSLR?

Most astro sites sell JMI stuff.

Pick out a JMI moto-focus here http://www.jimsmobile.com/buy_motofocus.htm Will come with hand controller to focus if standing near telescope.

Can see the JMI PCFC here http://www.jimsmobile.com/buy_motor_controls.htm#PC_Focus_Control You unplug hand controller and plug in PCFC to moto-focus and pc.

Below is a pic of what the pc control looks like on your pc screen.  Works perfectly for remote wifi focusing.

Also below are couple examples how they attach.  Different for types of scopes.   For crayford focuser on my refractor it just slips over fine focus adjustment and mounts to existing bolts underneath. For sct it replaces focus knob.

Like colors in first image and person standing in 3rd image.  Did you yell at the guy to get out of your shot?

Nice of you to feed the bugs.  Some good captures, iso 100 may have tamed that bit.

Ohh that came out nice.  Like the moon with GRS.

Great image, like the blending of shadow side details.

Not sure its most inexpensive but AVX is good light weight mount for moving around yard imaging planets.  Can accurately polar align from anywhere in your yard with only hand controller. Polaris not needed.

Other night wanted to image ISS crossing moon.  Moon was low so trees would be an issue.  Noticed Jupiter was only 1 degree higher than moon and on same trajectory so looked at alt/az coordinates of moon when pass happened.  Moved Jupiter in stellarium to that position and noted the time (about an hour earlier).  Went outside to see where Jupiter centered up between trees at that time.  Set up AVX mount where I was standing - Jupiter in center of tree gap.  Only views I have in this spot is partial South, SE, SW and up.  Used all star polar align in hand controller was able to accurately polar align with no view of Polaris or N, E or W.  I captured the pass, was quite pleased with myself.

Enjoy being able to set up and polar align anywhere in yard.  Not very good mount for long exposure imaging.

Also like the images poking thru clouds, very nice!

5 hours ago, Skipper Billy said:

I have the same size drive as you and run the cleanup inc remove old system files on a regular basis - never any issues.

You have probably realised that you cant install the latest update '1903' as the drive isnt big enough - 1903 needs 23gb for the OS and 7gb reserved for future updates.

 

I gained 4 G up to 10 now.  Message says pc not ready for update 1903 yet nothing I need to do at this time.  Maybe a smaller update in the works.

Have win 10 stick pc with 6 G free of 28 G on C drive.  I do regular disk cleanups on it to free up small amounts of additional space.  An option recently popped up to free up 30 G by cleaning "windows update cleanup".  Could finally use for higher speed captures which require more storage.  Obviously don't want to do this if high degree of risk involved.  Right now all astro programs work and not very capable of fixing anything if something goes wrong?

Looked at it again, now says can free up 3.45 G not 30 G. Weird..

You don't need much to get up and going or anything fancy / expensive. 

1. Power in your obs (battery or live) to power mount and pc.

2. Old laptop or small pc in Obs to connect mount and camera to. 

3. PC in home plus program to connect them. 

4. Free program to control mount like ASCOM / EQ Mod / Stellarium scope. 

5. Free program to control camera like Sharpcap or Firecapture.

6. Optional - Motorized focuser control like JMI pc focus control.

I don't have an Obs but if its cold or mosquitos are bad I do remote.  Pic of small set up I use for viewing taking few snap shots.  Azulle stick pc on left and optional small battery pack on right to run it.  Can also run on 12v power tank that runs mount but with small battery pack can strap all to scope and not worry about cord wrap. Stick pc came with win 10 pro so I use remote desktop connect. Other programs are avail to connect 2 pcs. This stick pc has 2 usb3 ports, a LAN port, HDMI connection and micro sd card port.

For serious imaging you will want something with more usb ports/storage.  Use Kingdel mini pc for times I want to guide and focus remotely, it has 4 usb3 ports and 1 usb2 port. 

Intl space station crossing moon this evening, about a second for entire transit.  ED80 refractor - asi 178mm - mono8 avi - flattener - no filter.  Glad to capture, just didn't give myself enough set up time for optimal settings.  Connected camera / started sharpcap had 30 seconds before pass to focus, set gain/exposure/hit capture.  Exp bit high - gain bit low so not best detail.  Almost made it across before frames started dropping like flies. 

I like cropping elongated stars out of my AVX captures.  Yes this confused me early on especially using Stellarium.  Switching between cameras the selected object in Stellarium would be different sizes in the frame leading me believe one camera would give me greater FL . 

I like the core detail with faint stars coming through. 

Not much activity wise, sun was shining though.  CS.

3 hours ago, Anne S said:

My Thousand Oaks filter came with a couple of Velcro strips attached which attach to ones on the dewshield to keep the filter in place. Could you do something similar to stop it happening again?

It has 3 plastic thumb screws to secure it into place, supposed to screw them in.  Made of cardboard and weighs nothing, but if thumb screws are tight wind cant move it.  

5 hours ago, Alan64 said:

The Celestron CG-3 mount, is the same as an EQ-2.  It may that the mount's axes, along with the worm assembly, are bound up.  They tend to ship like that from the factory.  Here's how to adjust them...

https://stargazerslounge.com/topic/319273-meade-large-equatorialeq-2-hyper-tuning/?do=findComment&comment=3492379

Great demonstration of hyper-tuning.  I have EQS version which worked manually out of box but slow motion controls were very stiff.  The RA worm was binding on the gear needed adjustment loosening retightening 2 bolts you demonstrate.  Now clock drive works smoothly will eventually clean factory grease out and re-grease then same for DEC. 

Great image! Definitely a win, well planned and delivered considering conditions.