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As my GoTo is successfully finished (some cosmetic issues remain) I shoud focus my attention on planets' positions. I have proper source of information: fantastic book "Astronomical Algorithms" by Jean Meeus, thus I will sort the planets soon. But planets are not a challenge for me at this moment, they are just something obvious to do in my list.
I have another idea and ambitious plan for next project within the year: locating and tracking the ISS to be able to make a video of its fly, not only transition.
Similarly to other objects, I need some equations. I'm pretty sure they are available somewhere, because plenty websites or apps offer showing current position of the ISS.
I will use this topic for sharing a progress ot the project.
By Cosmic Geoff
I have had an issue with the mount of my CPC800. I have noted that sometimes when slewing through a large angle in azimuth the note of the gear noise changes. Also once or twice the target image has taken off to the left while I was preparing to image and even motor speed 3 would not hold it on screen. Also I have once or twice left it unattended for several minutes and returned to discover that I needed to use the optical finder to recover the target. This makes me wonder if something is binding.
It still works far better than the 6/8 SE mount, so I am reluctant to send it for repair or open it up without a clear pointer to the nature of the problem and likely fix. It would be a more serious issue for long exposures/deep space imaging.
I have an EQ5 telescope mount which i use for astrophotography. I have modified it with a motorised RA axis using a bipolar stepper motor - my thread for the build is here .
I want to expand the mount's tracking ability by motorising the DEC axis and using a guide scope/camera. I generally use the mount in fairly remote locations so would like to use a raspberry Pi for portability.
I understand that I'll need to use a Raspberry Pi Camera Module for the guide camera.
The capability I want is:
1. guide the mount along RA and DEC axes using a guide star as feedback
2. track the mount using the RA axis only, and if possible continuously take 20-30 second exposures on the guide camera (this functionality is optional, but would assist in polar alignment of the mount)
I don't want any GOTO capability. I am very new to RPi and need some help:
- do I need to write code for this, or is there existing programming available for what I want to do?
- is it possible to avoid the use of screens (in the field)? My preferred option would be to flick a switch to start and stop the guiding, with another switch for alignment mode (or something simple like this).
- do I need to use any particular stepper motors/drivers for raspberry Pi? I'm using a bipolar stepper motor running quarter steps, with an A4988 stepper driver
- is the RPi 3 Model B+ the unit I should buy?
Date: Tuesday 29th Jan 2019. 2015-2315hrs
Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
Night Vision: PVS-14 with Photonis 4g INTENS.
Eyepieces: Plossl 55mm (f2 x38), Panoptic 35mm (f3 x60).
Filters: Chroma 5nm Ha filter.
Make Hay While The Sun Shines.
The Weather forecast changed and was now showing as two clear cold nights coming my way. I have had a couple of sessions already but we all know that you must “make hay while the moon is away” in this game!
My plan was to hit Orion hard and make up for the disappointment of the windy night last Sunday which kept me inside until Orion had passed the drop-down side of the shed.
Tonight I also planned to bring the Panoptic 35mm into play for a little more magnification (x60) on my chosen Ha nebula targets.
An Initial Run with the 55mm Plossl.
I had myself setup (in the shed) and aligned (Nexus 2-star) by 2015hrs and loaded the Chroma 5nm Ha CCD filter onto the Paracorr2. Then inserted the 55mm Plossl and attached the PVS-14 Night Vision Device to it using the TNVC a-focal astronomy adapter.
Flaming Star – First up was the Flaming star. It provided a decent view with some wispy fine detail including the two right angles of the back corner and multiple bright fuzzy lines at varying angles within). The 3D view of “my best outing” was not repeated on this occasion so I determined that the sky was not “at its best”.
IC410/417 – I nudged over to IC410 which was looking good with three black holes on one side and another large black hole on the other side. The nebula was more lush than the Flaming star and I enjoyed the view. Over to IC417 where the “spider” was visible but again not “at its best”.
M1 Crab – I headed down to the Crab and was rewarded by 5 nice ovals shapes interlinked in a bubble like structure. It took time and averted to tease out the outer bubbles whereas the central bubbles were much easier.
NGC2174 Monkeys Head – Over to the Monkeys Head and I was greeted with a very bright and “in your face” view of a neanderthal man. The edges of the facial features showed several bright areas. There was a tiny nebula spot set away from the mouth and a bright spot around the “ear”. The larger right patch to the neck (that I have seen previously) was there but took some averted to see it.
Sh2-269 – small bright “angels wings” shape.
Sh2-267 – medium sized faintish patch.
Sh2-268 – Faint and large. Like an upside-down pear drop. I could see black detailing inside around a line of bright stars.
Sh2-270 – FAIL. I am missing this Sharpless object and I failed to find it once again! I found a “candidate” but internet research this morning says that it was not it. I have compared sky safari location to an image and it seems they are slightly out so I have added a marked into sky safari ready for my next attempt. This object is only 1’ x 1’ size so maybe I need more magnification?
HorseHead IC434 – Up to IC434 and Wow it’s really wide and bright. I nudged above Alnitak and there was a lovely shapely horse head. The head showed the snout and neck but I was also attracted to the bright white line that was running through IC434 as it was really standing out. As I nudged around, it really was amazing to see just how long and wide IC434 actually is. The whole of this region is just full of a faint nebulosity glow.
Flame – I nudged down to the Flame and at last it was a view to savour. My last couple of visits have been underwhelming but tonight it was standing out bold as brass. I could make out many wispy black details to the RHS and see the small black circle to the LHS. It really was nice but I had to go back to the horsey as it was probably “beating it” for loveliness tonight!
M42 – Fantastic. I swore out loud as M42 swung into view. God its bright and God its lovely. The swirling, looping nebula behind the fish head is overwhelming. The ray of black hydrogen spewing out of the mouth of the fish head is like an “oil leak”. There is so much to see that I settle in on my chair and let it float across my fov several times as I try to tease out a detail that I have not noticed before. Tonight I settled on a couple of black areas to the LHS lower of the fish head. I even though that I could see the Candle Star sitting in the fishes mouth. I could see all 4 trapezium stars clearly so maybe the transparency was improving…
Running Man NGC1975 – Time to get into Orion and start with my on-going challenge to see the Running Man. I am gradually building up more mental notes to help with seeing this difficult target. I could easily see a very bright patch sitting over three stars below M43. I could see a black finger coming down the LHS of the 3 stars. I got distracted by further nebulosity down underneath an open cluster below and became confused as to where the black legs of the running man actually are?
Sh2-278 – Triangular kite shaped nebula but faint and time needed to get to grips with it.
Time to Increase the Magnification with the 35mm Panoptic.
The image presented by the 55mm Plossl (when used with Night Vision and a fast focal ratio scope) leaves a lot to be desired especially around the edges of the fov. The 35mm Panoptic does not suffer from these issues and provides a sharp edge-to-edge view. However, the 35mm only acts as a 0.7x reducer so some image brightness is lost compared to the 55mm Plossl. Therefore, you need to use more “gain” (a knob on the PVS-14) to compensate for the darker image. From my experience the 55mm Plossl seems to always win out because the brighter image just shows more stuff and I just ignore the outer edges of the FOV.
Flaming Star – Back to the Flaming star and I could see some nice texture and details within. The larger image scale meant more nudging was needed and I felt that I preferred the 55mm on this object.
IC410 – Very nice and the extra brightness of the nebula meant that nothing felt lost on this target. I felt the 35mm was the winner here.
M1 crab – A nice view. The bubbles were now a little larger but I felt that I was not seeing more than with the 55mm so I will call this one a tie.
Fox Fur/Cone – With the 35mm loaded, I wanted to see if I could get more from the Cone than the other night. I started at the central star cluster and nebulosity was showing all around except for near the bright stars which seemed to have cleared a nice black patch over them. I nudged up and right to the Cone. It was pretty obvious as it came into view and a decent size too. It felt like it was an inch long and both sides were clearly visible running to a sharp multi colored double at the point. (With NV I cannot see colors but I can see shades and it was noticeable that the double stars were not the same color). I played with the gain control trying to get more out of the cone with not much success. It’s a difficult target and although I could see it easily, if the same view had been presented to my wife then she would have said “where is it?”. I nudged left and right in long sweeps for a while as I tried to cover the area of the Fox Fur nebula (Huge) and see the many lanes of bright nebula within. There was plenty to see but I prefer the Fox Fur view in the Borg107 where I can more easily take it all in.
Rosette – Holy Cow, the highlight of the night! I would have to say this must have been my “best ever” view of the Rosette even allowing for the fact that I had to nudge around it thanks to the extra scale of the 35mm Panoptic. The Nebula was so lush and large. The extra magnification really allowed me to get deeper into the many intricate black lanes that run within the lower and left sides of this nebula. I found further black areas to investigate in the upper RHS. And I noticed three small nebula patches embedded within the centre star cluster (RHS) which I have not noticed previously.
Sh2-280 – Nudge down to a large nebula patch with two black eyes. The RHS edge was brighter and also below.
Sh2-282 – Nudge down to a triangular patch on its side. 4 stars were carving out a black area behind the tip.
Sh2-283 – A tiny bright patch (located at star HD291952 in Sky Safari).
IC434 – Over to view the horse head with more magnification and I was not disappointed. The Horse was there in all its glory – snout, neck and an ear. I let it drift across the view a few times. I also noticed that if I turn the “gain” down then the outer edges of the horse head took on a brighter glow? A win for the 35mm here.
Flame – Up to the Flame which was big and bright. I think that the 55mm Plossl view was slightly more feature-ridden and the loss of focal ratio had taken something away. It still looked great though, don’t get me wrong!
Running Man – Back to the nemesis that is “the Running Man” and unbelievably I was able to tease out some black edge detail. I could see a vertical piece LHS and a longer horizontal piece under the three stars (more RHS). The black lane seemed to reach up and touch the middle of the three stars too. Another win for the 35mm.
M42 – You have to don’t you? A great view but with diminished resolution compared to the 55mm Plossl IMHO.
Medusa – An easy black crescent. It had a very bright tip at the bottom and also a less bright tip at the top. The Crescent sides seemed incomplete and I chalked this as another win for the 55mm.
Sh2-241 – A small bright patch with a central star and a black area within.
Sh2-242 – A mid-size patch with an off-centre bright star within.
What Happens when you View an Open Cluster with a 5nm Ha Filter?
By now I was getting cold and Orion was passed the drop down side of my shed. I headed up towards the zenith and decided to view M37 with the 5nm Ha CCD filter still loaded on the Paracorr2.
M37 – A lovely bright open cluster fills the fov of the 35mm Panoptic. As I turn the gain down on the NVD something interesting happens… A black lane structure appears running in some of the gaps between the stars of the cluster. It takes on an appearance more reminiscent of Caroline’s Rose with conventional eyepieces. I continue to play with the gain. It seems some stars are within nebula lanes/patches and some stars are within or next to these black (Hydrogen) lanes. I stood there pondering whether the stars were clearing the nebula to reveal the blackness or the blackness was somehow connecting lines of stars within the cluster?
M35 – Onto another nearby cluster M35. Once again, the same thing. With the gain down then black snaking lanes appear within the cluster. But there are lanes/patches of nebulosity too (or is it reflecting dust?)
IC443/444 – I finished with a short hop over to one of my favourite objects, the Jelly fish, IC443. Wow, the detail showing within the pancake of the Jellyfish was great. The flat head had two clear sides and dimmer/blacker areas within. There were some shimmering brighter bits too. The outer edges had clear definition as it steps down and curves away. I could see a single thread heading away from the pancake head towards IC444 and followed it away from IC443. I eventually ran into four thick parallel lanes of nebula near the strangely named “Tejat Posterior” star. I went back to IC443 and followed the tentacles running away to the left this time.
Thoughts of the observer.
It was nice to get some use from the Pan35 at last. I seem to robotically load up the 55mm Plossl these days. I did prove on several targets that the extra magnification of the 35mm Plossl cannot compensate for the loss of focal ratio provided by the 55mm Plossl. BUT I did also see some benefit on several targets notably the Rosette, Horse Head & Running Man. Looks like I need to use both. The dark lanes in the open clusters M37 & M35 were an unexpected bonus and I think I will be trying the 5nm Ha filter on other non-nebula targets (M45 & M13 for instance) in the near future. I have looked on the internet for some Ha images of the open clusters but nothing was immediately found that showed what I was seeing? Perhaps one of the NV phonetography guys can get a shot of this feature? Its forecast clear again tonight so I packed up early so I could get some sleep in preparation.
Hope you are getting some clear skies too?
Date: Sunday 27th January 2019. 2230-0215am
Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
Night Vision: PVS-14 with Photonis 4g INTENS.
Eyepieces: Plossl 55mm (f2 x38).
Filters: Chroma 5nm Ha filter.
Moon: 46% (from 0130am)
Make a start on Milky Way Nebula.
As Orion was now past its best position from my shed, I headed straight into its heart to see the big hitters before it was too late! I had the 55mm Plossl and 5nm Chroma Ha filter loaded.
M42, M43, Flame, Horse head – Were all nice but signs were that the transparency was not at its best as I have seen them all better. Of course, I was not helped by the fact the shed wall was taking away some light from the big mirror.
Running Man NGC1973 – I got a fleeting glimpse of a bright patch around 3 stars and had just started to look for the black finger above and the two sideways legs underneath when cloud passed over and took it away. I stayed a few minutes but did not get the brightness back of the initial “look”. The fleeting glimpse did however give me some optimism that the Running Man can be observed directly if and when the conditions & location are right.
Rosette – The Rosette was another story. It was stunning – maybe my best ever view? – it was lush with nebula on all sides of the centre star cluster. I noted two brighter patches to the LHS and one brighter area to the RHS. The “black veins” stood out well underneath and I lingered a while to have a proper look.
Fox Fur & Cone – Another good one. The Fox Fur was large and I nudged around to try to see as much of it as I could. The Cone area was more of a challenge not helped by the fact that I started looking in the wrong area. The bright central cluster has cut a black area into the Fox fur and I was looking here for the Cone before I checked Sky Safari and moved up to the right to find the Cone, which was showing both sides well but still needed plenty of averted to appreciate it properly. Even with Night Vision, it’s still much tougher than the Horsehead.
Monkey Head & IC443 were next. Again they looked good but I have seen them better.
Then onto the Seagull, its low position from the shed making it a pretty faint target. The head and mouth were nice but the fainter Sharpless around the wings were beyond me. This is a target for the Borg107 which has no issues getting down so low.
Sh2-294 – This is a nice target. It shows as a midsize bright patch. There is a black section up the centre and it appears like a “rib cage” or “waistcoat” with two bright sides.
Sh2-291 – A much fainter mid-size patch. Some blackness inside. Has the appearance of a “curve”.
Sh2-289 – Brightish patch around a star.
Sh2-286 – small, faintish patch.
Sh2-287 – Large pear drop shaped. Varying black and bright within. Bottom edge is the brightest near a line of bright stars.
Sh2-288 – Very bright & tiny patch.
Medusa neb (sh2-274) – Fuzzy bright crescent outline with black interior. Seems to be hazy on LHS as if tendrils falling away. Nice target.
M67 open cluster with 5nm Ha filter still installed. I dropped onto M67 and it appears as a “clover” with three oval streams of stars catching the eye!
Next up, chasing some Comets.
It was now 0015hrs and the Milky Way had moved west of the shed, time to try some Comets using Sky Safari…
C/38P Stephan-Oterman – With the 55mm Plossl (x38) and no filter. I saw a small bright core with a surrounding dust head.
C/46P Wirtanen – The core appeared larger than 38P but with less brightness. A large dust head surrounded the core.
C/123P West-Hartley – I was unable to locate this comet in Ursa Major. I have updated Sky Safari Pro’s “comet orbit data” this morning so maybe I will have better luck next time?
Finally, back to the list of “brightest” galaxies.
Sticking with the "heated" 55mm Plossl and no filters. I moved onto my Sky Safari "bright galaxy observing list" ( Galaxy High Brightness.skylist ).
NGC2683 – Bright edge-on galaxy. Central bulge and appearance of black swirls to RHS.
NGC3003 – Small, faint edge-on.
NGC2841 – Bright side-on. Bright core & centre with swirls around. Hints of detail in the black patches seen above and more faintly below. Nice.
NGC2681 Helix – Initially, a small bright core is seen but with time at the eyepiece a circular disk appears away from the core. The gap in between the disk and the core is black. Great.
NGC2537 Bear Paw – This was an unusual one! Very interesting appearance of a small fuzzy patch. As you look then it appears like two circles drawn on different planes. It does look like a “paw”!
NGC3184 – ARMS! At last, some clear arms. There is a central core with halo surrounded by a black circle. The backward S shape of the arms comes into view after a few seconds…
NGC3432 – appears as a thin pencil line. The core is only slightly brighter than the rest.
NGC3254 & SN2019np – A quick revisit to the bright supernova in NGC3254. Tonight the SN is much brighter and easily spotted just outside the dust disk of the galaxy.
M95 – ARMS! A thick central bar leads to circular arms. The arms are brightest near the bar. The galaxy has a bright core.
M96 – A bright core with a circular disk. Circular arms are hinted with more time at the eyepiece. Faint arms start at the ends of the central bar. The best view of the arms is LHS where they are small and away from the centre. Black patches appear above and below the galaxy.
M105/NGC3384/NGC3373 – Two very similar bright galaxies with bright core and small dust disk (elliptical) and one fainter (core can be seen) but longer companion. This galaxy (3373) has swirly (spiral) features.
NGC2903 – ARMS! There is a bright core with a central bar (there are brighter areas at the ends of the central bar too). There is a clear double arm on RHS. A single arm is seen on the LHS (this may also be a double arm which seems to be coming & going). The arms are quite short. Great.
M100 – ARMS! Two faint and full swirling arms are seen with time at the eyepiece. This is a mini M51. Very nice.
M99 - ARMS! Two long circular arms are seen leaving the central bar of the galaxy.
M98 – A long edge-on galaxy. A bright core and bright patch to RHS. Swirly arms are hinted to LHS. There is blackness on both sides.
NGC4216 – Edge on galaxy with a bright core. Blackness on both sides. Another small edge-on galaxy is seen nearby.
By now it was 0215 and the light of the moon was lighting up the west side of my shed. I was cold and decided that I had had enough for tonight.
Thoughts of the observer.
1. It was a shame that I missed Orion as I was really looking forward to enjoying the Sharpless around that area. But I did at least get a decent session in before the Devils Orb appeared.
2. Once again, I was able to see clear arms in five more galaxies with definite “hints” in others too. The key seems to be to spend time at the eyepiece and don’t have the gain turned up to much on the PVS-14.
3. It was great to get two comets into the mix. But a tinge of disappointment that I failed to bag a couple more…
4. The supernova in NGC3254 was easily seen – another highlight. I did try for the “other” supernova in UGC7534 but the Plough had not come around over the shed roof so I was severely restricted with light gathering abilities. I need to try after 3am to get any chance (or relocate the dob on the shed floor).
5. It was a pretty cold night (-2) with heaters running on the secondary and eyepiece. The scope had a layer of ice to be wiped off once I closed the roof and put the light on.