With weeks of dismal conditions in SF and good forecast for Sonoma, we decided to go back to Sonoma.
This time I wanted to do some EAA with several possible improvements I worked on in the past week but never actually tested:
- a new fine grit anti-slip tape (see [1])
- the "raiser fix" (see [2])
- the Optlong L-Enhance filter (see [3])
We left around 6:15pm. The drive was easy (practically no traffic). We got there around 7:45pm (15' after Sunset) which left us enough time to setup before the start of the astromical night (9pm). The sky was clear and the temperature pleasant: I never had to put on extra layers. The air was quite dry also, no dew formed at any time. But unfortunately there were gusty winds. Initially I thought I would have to give up doing EAA and go back to visual (like I did in Sonoma IV). But I actually managed to keep going as long I kept the subframes short and watched the stack closely to drop bad frames. I started using the new L-Enhance filter after the first few targets. It required a different ring on the focuser and a focus re-adjustment, so I just left in on for the rest of the evening. It seems to help for dimmer targets. For instance I got my best picture (so far) of C27.
We left around midnight and were back by 1:30pm.
Observations
- M28 and M22 Globular Clusters - Sagittarius
- M19 and M62 Globular Clusters - Ophiuchus
- M6 Butterfly Cluster - Scorpio
- M9 Globular Cluster - Ophiuchus
- M20 Trifid Nebula - Sagittarius
- M8 Lagoon Nebula - Sagittarius
- M16 Eagle - Serpens, M17 Omega - Sagittarius, first without filter and then with
- IC 1284 Nebula - Sagittarius filter
- C27 Crescent Nebula - Cygnus - my best image to date filter
- C20 North America Nebula - Cygnus - not convincing out of ASILive, but when I picked the best 25 frames and stacked in Siril, I got a better result
- IC 1396 Elephant Trunk Nebula - Cepheus - pretty good
- C4 Iris Nebula - Cepheus - underwhelming - might have been better without filter
- C11 Bubble Nebula - Cassiopeia - finally the (almost) full bubble
- C9 Cave Nebula - Cepheus
- NGC 7380 Wizard Nebula - Cepheus
- Mel 15 Heart Nebula - Cassiopeia
- IC 1848 Soul Nebula - Cassiopeia
- M31 Great Andromeda Galaxy - not great with the filter
- C63 Helix Nebula - Aquarius
- C33 East Veil Nebula - Cygnus - magnificent - quite visible in single frames already
- C34 West Veil Nebula - Cygnus - a beauty
- M27 Dumbbell Nebula - Vulpecula
- M57 Ring Nebula - Lyra - just okay
 |
| M28 30x1s |
 |
| M22 Great Sagittarius Cluster 30x1s |
 |
| M19 30x1s |
 |
| M62 30x1s |
 |
| M6 Butterfly Cluster 15x1s |
 |
| M9 30x1s |
 |
| M20 Trifid Nebula 34x3s |
 |
| M8 Lagoon Nebula 40x3s |
 |
| M16 Eagle Nebula 40x3s (w/filter) |
 |
| M17 Omega Nebula 54x2s (w/filter) |
 |
| IC 1284 75x2s (w/filter) |
 |
| C27 Crescent Nebula 76x2s (w/filter) |
 |
| C20 North America Nebula 25x3s (w/filter) |
[stacked in Siril - chose 25 best of 61] |
 |
| IC 1396 Elephant Trunk Nebula 83x2s (w/filter) |
 |
| C4 Iris Nebula 43x3s (w/filter) |
 |
| C11 Bubble Nebula 90x2s (w/filter) |
 |
| C9 Cave Nebula 72x2.5s (w/filter) |
 |
| NGC 7380 Wizard Nebula 65x2.5s (w/filter) |
 |
| Mel 15 Heart Nebula 52x2.5s (w/filter) |
 |
| IC 1848 Soul Nebula 60x2.5s (w/filter) |
 |
| M31 Great Andromeda Galaxy 50x1s (w/filter) |
 |
| C63 Helix Nebula 60x2s (w/filter) |
 |
| C33 East Veil Nebula 75x2s (w/filter) |
 |
| C34 West Veil Nebula 90x2s (w/filter) |
 |
| M27 Dumbbell Nebula 75x1s (w/filter) |
 |
| M57 Ring Nebula 49x1s (w/filter) |
(1) The second time I went out with the raiser, I could not increase the subframe time past a few seconds, unable to go back to the 10s I managed the first time out with the raiser. It did not know it it was the wind or the anti-slip tape or a combination of both. I ordered some fine grit anti-slip tape. I was unable to wrap it around the powered axis (it didn't quite stick to itself), so I used it only on the segment and used the old medium grit tape on the axis.
(2) A week ago, I got an email from the builder of the EQ platform. He looked at the picture I posted on this blog and said I had not installed the raiser properly. The top part of the platform should remain parallel to the ground (for stability) and having the pivot point up and back should be enough to lower the altitude (angle with horizontal in a vertical plane) of the axis of the platform. I did an experiment at home. I took apart the head of my photo tripod, mounted the red collimation laser in the laser bracket on top of it, and sat it in the "south shoe" on the platform. Then I pointed it at a wall and try and figure out the altitude angle at which the dot no longer moves when the platform is fast forwarded - I got something like 48 deg without the raiser, 35 deg with my initial raiser setup and then got it to 38 deg with a more horizontal top platform. Right before heading out, I "tested" with the telescope on top and realized that half way through the run the segment was rubbing against the thing holding the axis. But there was no time to try and detach / reattach the raiser to move the pivot point back. I would just have to reset the platform more often.
(3) After reading some research comparing Optlong filters, I decided to purchase the L-Enhance, it seemed like a good compromise of price vs performance, also its band is not so narrow that it would require longer exposures that I can manage.
