Jump to content

Narrowband

Asellus

New Members
  • Posts

    6
  • Joined

  • Last visited

Reputation

29 Excellent

Profile Information

  • Location
    Scotland

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Last year I had a go tilting images of craters near the edge of the limb to get a simulated top down perspective. I realised that if you had a full disc image you should be able to map that on to a 3D solid hemisphere and then rotate that hemisphere to get a top down view anywhere on this side of the moon. Below is my attempt to do this using blender (a 3D modelling and animation tool). Original "flat" image is a mosaic using a 12" Orion Optics UK newtonian at about f26 and an ASI294mc processed in AS!3, RegStakx, GIMP. 3D projection and animation done in blender. The original image had a very favourable eastern libration that allowed you to see to about 90 degrees east. Worked pretty well so going to have a go at a few more of these! https://youtu.be/A_6UvuSUYSY Searching around the web, I am by no means the first person to do this. The earliest I found were workers at the University of Arizona in the early '60s working on the "Rectified lunar atlas" who projected photographic images down a long dark tunnel onto a 3ft diameter sphere. They then stood at the side of the sphere to photograph the limb top-down. https://www.psi.edu/epo/multiring_impact_basins/multiring_impact_basins.html There was also this post on SGL from a few years back using the Lunar Terminator Visualisation tool to get single top-down images near the limb:
  2. I have a Lunt Herschel wedge on order. Will be interesting to see the improvement to the Baader filter when it eventually arrives. Hopefully it's not just "subtle" as it's a fair amount of a price difference.
  3. Sun is slowly climbing higher in my sky. Manage to (just) get images in white light (WO GT71 2x barlow Baader safety film filter - ASi294mc) and H-alpha (Lunt LS60THA B1220 2x barlow) at around midday before cloud rolled in on both days.
  4. Mosaic of 10 images. Orion Optics 12" newtonian operating at about f/16 (native f5.3 + 3x Televue barlow). ASI294mc. Planning on a focuser upgrade soon to make it a little easier sustain a sharp image.
  5. I was imaging the moon a couple of weeks back, looking at Clavius and having a read of Wikipeadia. They have a Lunar Reconnaissance Orbiter image from directly above. I was wondering if I could some how warp my image to get something similar. Thinking about it I realised that if you take the latitude (north/south) and tilt the image left-right by the same angle you'll locally remove that destortion. You can do the same with longitude (east/west) by an up-down tilt of the same angle giving an approximate view from directly above, but with a smaller image (see below). This works OK at the exact latitude/longitude but destorts the rest of the moon the further you are away from that point (like it's in a hall of mirrors at the fair ground). Results for Clavius (58.4°S 14.4°W) were OK. The image below shows a blow up of the original image, the tilted image, and an image generated from the NASA LRO data https://quickmap.lroc.asu.edu/ . My method was align my original image North-South (did this by comparing a couple of features from the NASA SVS daily image ( https://svs.gsfc.nasa.gov/4955 ) - you can actually use these images to have a play with tilting in the image software of your choice if you don't have a handy image of your own. Then used the 3D Transform tool in GIMP to tilt the image 58.4 degrees left-right and 14.4 degrees top-bottom. There are two options here either +58.4 or -58.4, both work but once chosen only one of + or - 14.4 works. They produce very similar results, but one of +/- 58.4 looked slightly better to me. You also need to correct for libration, but I found as my original north-south alignment was never totally acurate once I'd dialed in the latitude/longitude it was best to pick a small craterlet somewhere near the centre of the region of interest and just tweak the left-right/up-down tilts a little by hand to make it circular. Results at the bottom 🙂 Obviously once this worked I had a play at how close to the limb you can get (the answer is very!). I've got some more examples if people are interested.
  6. Managed to get a couple of shots of the sun yesterday around midday. Still very low for me (a bit less than 20 degrees) but fairly please with the results. White light is an ST80 with a Baader safety film filter over the objective. The H-alpha are two images (disc & limb), roughly stitched together in GIMP, using a Lunt LS60THA (B1220). ZWO ASI294MC for the capture with ASICap. About 400 frames in each case stacked in AutoStakkert!3, wavelets & a little histogram stretch in RegiStax6.
  7. Hello from a fellow new member. On the question of white-light solar observing an option may be to start with solar projection - stopping down the objective of the scope and focusing the image of the sun onto a piece of white card. I started this way (and continue to use this for visual observation). It's easy and safe (not that other methods aren't if done correctly). It also gives you a healthy respect for being carful with solar observation. I've observed and drawn many sunspot groups by this method. Just an alternative starting point 🙂.
  8. Thanks for the warm welcomes. Not a permanent setup at all, everything in taken out to a sunken garden which gives good protection from the wind & what little local lighting there is. Takes about 45 mins - 1 hour to get up and running & 20-30 mins to get it all back indoors. That includes getting the stream up too. If it was just the mount/scope/cables would be 10 mins or so less. The longest single part is probably polar alignment, but using Sharpcap's plate solving for that isn't too bad. Once set up and focused everything is controlled from the living room through a 15m USB cable to a powered USB hub at the scope. I've basically got use to it so mostly am running on "automatic" now. In all honestly setting up streams for other things takes about the same time - so, though it might seem a long set-up/break-down, my mind doesn't see it that way. 🙂
  9. A bit of an introduction. I'm based on the east coast in Scotland & had been doing visual astronomy for 20+ years - mostly an Orion Optics 300mm f5.4 Dob. I stopped for a while (logbook says October 2008), but just over a year ago dug out the telescope to show some friends on Twitch some views of the moon. My eyesight is not quite what it used to be and so now I've mostly switched from visual to EEVA. I'm enjoying doing astronomy from the living room! Current set-up is either the Orion Optics 300mm now on an EQ6R pro or an WO GT71 on the same mount. Using an uncooled ASI294mc for capture with a mix of ASI and Sharpcap software depending on the target. August to May I’ve mainly being doing deep-sky EEVA and lunar lucky imaging. Over summer when we don’t have any night to speak of, I’ve switched over to solar white-light, and H-alpha (Lunt LS60TH). I’ve been streaming a lot of my sessions on Twitch for friends on there and it’s been very good motivation to keep going and get set up outside even if the conditions are not ideal - I think that was my original downfall. As with everyone I’m still learning lots as I go along and have found Stargazers lounge a really useful source of info over the years. A big thanks to you all for that! You may not realise it but you help out an awful lot of people who just lurk here - both new and old to the hobby. I’ve not done a lot of deep-sky astro-imaging – I don’t think I have the patience or skill for that. Apart from their general beauty, I guess a lot of my interest is trying to get to know a bit of the science behind the objects. Hopefully I’ll be able to post something interesting in the solar/lunar/EEVA sections in the coming weeks.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.