What's New



Odds n Ends

       Planetary Nebula in Cepheus 
       RA:23h 55m 44s  Dec: +80 29' 50" Distance ~929 ly  Size - ~20'

Click on image for larger size
  Sh2-174 known as the Valentine Rose Nebula was discovered by Stewart Sharpless and is also cataloged as PK 120+18.1  This is an interesting planetary nebula in that as with many planetary nebula, the central star can be found near the center. In the case of Sh2-174 the white dwarf star (GD-561) is offset to the right and is seen as the blue star in the center of the blue (OIII) ionized oxygen. The ionized oxygen region exhibits very visible bow shocks while the edge of the red Hydrogen regions show turbulence as it interacts with the interstellar medium.

  This was a challenging image to capture and process. To minimize field rotation due to imaging close to the pole, I found 10 minute sub exposures worked the best for the narrowband channels. The RGB channels each were limited to 3 minute sub exposures to preserve the colors and prevent CCD blooming.
This is a composite of 6 hours each for Ha and OIII and 36 minutes for each of the RGB channels that were used for the star field. Russell Crowman's StarXTerminator was used to remove the stars from the Ha and OIII narrowband channels. This allowed more aggressive stretching without worrying about bloating stars.

Location & Date
Backyard, Abbott Observatory- Long Island, NY,  December 2021
TMB130SS F/7 APO, Moonlite focuser, Losmandy G11 Gemini
Image scale 1.54 arcsec/pixel
Baader  Ha OIII RGB  filters
CCD temp -15C
Ha- 40x10m  OIII- 40x10m  Red-12x3m  Green-12x3m  Blue-12x3m Bin 1x1
Planning & Acquisition
Image planning - Sequence Generator Pro
Image acquisition - Sequence Generator Pro & PHD2 (guiding)
CCDStack -  Calibration, debloom, align, stacking, deconvolution
Adobe Photoshop -   Ha+OIII (HOO palette) RGB combine
RC-Astro StarXTerminator

SH2-174 Ha initial stretch and stars removed using StarXTerminator

SH2-174 OIII initial stretch and stars removed using StarXTerminator

2022 Michael A. Siniscalchi