1 Jan - Big Dob goes even deeper with the help of a Chroma 5nm Ha filter (Night Vision)

[alanjgreen]

Date: Tuesday 1st January 2019.   1845-2200hrs.
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 CCD Filter.
Moon: 0%

 

Introduction.

Seems like a long time since I saw a cloudless sky (because it is!). But last night was forecast clear and sure enough by 1830 the sky was clearing from the North via a light NE wind.

I had repositioned the dob for some Milky Way action earlier in the day and I quickly got setup with my Ethos10 to complete the 2-star alignment for my Nexus wifi device connected to Sky Safari 5.

I had a quick look at M33 to confirm the alignment and was pleased with the detail on offer, decent arms and several nebula patches showed within the galaxy at x200. The stars were pretty sharp too which is nice since the mirror still needed to cool to the outside temperature.

I switched to Night Vision, I added my new Chroma 5nm Ha filter to the bottom of the Paracorr2, then inserted the 55mm Plossl (and added the eyepiece heater tape that would surely be needed later), then finally attached the PVS-14 Night Vision directly to the Plossl using the TNVC/Televue a-focal adapter.

 

Observing report.

The Milky Way had not quite cleared the shed roof so targets were limited to begin with, the California nebula was available so I started there!

• California nebula – WOW what a start! I was treated to my best ever views of NGC1499/sh2-220. Both long edges appeared 3D like real texture. There were occasional brighter sections along the edges. The “Whales Eye” seemed to have extra hollowness and depth. I discovered a new protruding section to one end that I have not noticed before. I found that I preferred the view with the gain down as more features were easily seen than with the gain on full which made things a little too bright for my observing eyeball.
• LBN749 – Barnard 3 and 4 – Not sure that I have ever observed this target before but it was nearby so rude not to. I saw a decent sized nebula patch around the star Atik. The nebula surrounding the cluster was easily seen in direct vision (Barnard 3). Averted revealed a line of nebula out (Barnard 4) to a single star the other side of Atik. It was hard to see any nebulosity near Atik itself as the star was so bright.
• Sh2-238 – Hinds Var neb – A challenging object. I was able to see a faint patch next to a star. I played with the gain but was unable to get much more from the target.
• Sh2-246 – I observed a long vertical patch. It had a curved bottom and the top left corner seemed to come to a point. The outer edges were easily seen and traceable. Many black sections had been cleared by stars incl. a nice multi star patch bottom left.
• Sh2-215 – A faint patch embedded in a star pattern. Tough one.
• Sh2-213 – Two double pairs of stars with a faint patch in-between them. The patch is nearer the left pair and there appears to be a star with black surrounding it within the patch.
• Sh2-216 – The nearest planetary closest to the sun. It was bigger than the fov of the Plossl! It seemed to be almost half moon shaped. The edges were clear.
• Sh2-221 – Large “Africa” shaped patch with clear edges. Upper section contains intricate black lanes within.
• Sh2-219 – Small bright patch with a central star (sits at the side of sh2-221)
• Sh2-217 – Medium sized patch easily seen. Central star in a small black central region.
• Sh2-212 – Very bright fuzzy patch of medium size. Two stars seen within the patch.
• Sh2-211 – Small bright patch easily seen.
• Sh2-210 – Large nebula patch with a black area inside it. It sits next to a very large area of nebula making it hard to separate which is sh2-210!
• Sh2-207 & sh2-208 – A medium size patch easily seen with a very small patch to the side (easy to miss).
• Sh2-209 – Patch with a central dark area (to the right hand side). A black elephants trunk is entering from the left hand side.
• Sh2-206 – Nice. A star appears almost entirely surrounded by nebula (just a tiny gap is there). A very bright section dominates the view. Turn the gain down to reveal a fainter section around the star. This one deserves a revisit with more magnification (but once the heater tapes/gloves are on then I cannot be bothered with changing eyepieces!)
• Sh2-218 – Sky Safari has this correctly located. It is large and is shaped like a “fat sausage”. The top section appear pretty empty of detail.
• Flaming star (sh2-229) – WOW! Almost 3D like appearance. Wonderful bright “line” details within and plenty of “bellowy clouds”. New detail (for me) seen as we enter the tail section. I can see a double corner section and tiered sides to the tail. This has always been a disappointing target for me but last night I appear to have broken my duck – it really was wonderful. I now need to revisit and see if I can tease more out of the surrounding area (sh2-230).
• IC410 – Another best ever view, so much more contrast on offer. The nebula is thick and lush. There are two black eyes peering out at me (one eye is actually made of three dark patches with averted). The left cheek is very bright as are the tadpoles. There is a horizontal line seen underneath (not noticed this before) that seems to underline IC410. Great.
• IC417 – Another nice target. With the gain turned down, I can see a beautiful spider (or maybe an octopus?) with two stars for eyes. Nice.
• Sh2-237/NGC1931 – “The fly”, small and very bright.
• Sh2-235 – bright, decent sized patch easily seen
• Sh2-231 – sitting next to 235. Larger patch but quite faint.
• Sh2-233 – sitting next to 231. Tiny patch. Faint, has a central star.
• Sh2-232 – sitting next to 235. Large faint patch. Seems to have two horizontal lines running through it!
• Sh2-241 – A triangular patch. I see a small black crescent inside. There is a small bright patch on the bottom corner.
• Sh2-242 – A bright patch. There is a bright star just off centre which has black surrounding it.
• Sh2-243 – FAIL. A triangle of stars seen but unable to get any nebula.
• M1 crab – Wonderful but small. I counted six elonged bubbles with bright edges within the overall patchy shape. Nice. Needs more magnification but I’m too lazy to change eyepieces.
• NGC2174/sh2-252 – The Monkeys Head was superb with new detail on offer to me. Firstly, there was a new bright circular section obvious at the lower/back of the “cheek”. There were two curved black lanes running from the forehead backwards and curving down “like hair line”. There were a number of brighter sections down the face “eyebrow, nose bridge, lips, bright dot near ear”. There was also a  new fainter section below which seemed to “fall away” from the main face features. Great!
• Sh2-247 – Faint, decent sized patch easily seen.
• IC443/sh2-248 – Another great view of this SN remnant. The front “Jelly fish” was bright and clear in direct vision with texture and fine details seen within. The tendrils that fall back towards the bright star was clearer than I have seen them before with no averted needed. The Jelly fish seems to be pushing against two waves of nebula as you pan to the right. If you keep going then you come to a large patch of IC444 which was also easily seen.

 

I had been noticing clouds building to the west and it was now that they were mostly all over, I had a play with the Rosette, Flame, Horse head and M42 through the clouds before I decided to call it a night and go watch the final of the Darts instead

 

Thoughts of the observer.

1. This was the first real run out for the Chroma 5nm Ha filter and it could be co-incidence that I had several “best ever” views of some targets that I have visited many times and am familiar with but I don’t think so. It seems this filter is a step up on the Astronomik 6nm Ha filter.
2. The Chroma filter works well with very low gain without scintillation and this allows the user to get the gain down to remove some of the overly bright features that may be disguising fainter darker features around them – I like it. The Horse head really came out as a black horse once I got the gain down but I need to do more experimentation without the clouds.
3. I really enjoyed finally getting some mileage out of the “Flaming Star” which has never really blown my socks off. It really had depth and a 3D feel to it! I look forward to exploring that whole area next time out…
4. The Chroma filter really made IC410 better as the central black areas were just there in direct vision, previously I have needed some averted to get into the blackness. And the spider IC417 was just “in your face”.
5. I thought I had seen as much as I could from the Monkeys Head but apparently there was more to be seen and it really was a joy to suddenly encounter several new features.

 

Wishing you a happy 2019 & clear skies,
Alan

[Littleguy80]

Fab report, Alan. Happy new year to you too! I’d sure take some clear skies right now. This has been my worst run of not observing for some time. I’m sure they’ll arrive soon enough though. 

[Eastman]

Great report Alan, impressive list of objects to start yhe 2019 with.

Happy new year to you too.

[Stu]

Great report Alan! Good to see you picking up on Gavin's lead here, the 5mm Chroma filter is clearly a step up on the 6mm Astronomik so represents a good upgrade. Nice one.