Hemisphere:  Northern  ·  Constellation: Cepheus (Cep)  ·  Contains:  NGC 7023
Getting plate-solving status, please wait...
Iris and the Ghost (NGC 7023 to vdB 141 area), 



    
        

            snakagawa
Iris and the Ghost (NGC 7023 to vdB 141 area)
Powered byPixInsight

Iris and the Ghost (NGC 7023 to vdB 141 area)

Getting plate-solving status, please wait...
Iris and the Ghost (NGC 7023 to vdB 141 area), 



    
        

            snakagawa
Iris and the Ghost (NGC 7023 to vdB 141 area)
Powered byPixInsight

Iris and the Ghost (NGC 7023 to vdB 141 area)

Technical card


Basic astrometry details

Astrometry.net job: 698753

RA center: 21h 10' 20"

DEC center: +68° 5' 24"

Pixel scale: 5.542 arcsec/pixel

Orientation: 4.100 degrees

Field radius: 1.727 degrees


Resolution: 1920x1160

Description

This is my last image from C8 Fastar+Hyperstar combination, before the corrector plate got smashed during day-time collimation.... (sad)

C8 Faster (black)+ Hyperstar 3; SXVR-M25C at -15 deg C
An aperture mask was used to improve FWHM (F/2.1 increasing to F/2.66 [F/3 effective])
10min x 29
2min x 15

Slightly cropped near the bottom and the left for collimation errors.

A Hyperstar used with a large CCD chip (such as in M25c) results in strong light fall off which is difficult to correct with flats. The aperture mask improved this, making about 2/3 of the center field (linear) more or less flat. However, the fall off near the edge was still quite severe, the intensity dropping to ~50% of the field center. The original flats were adjusted slightly on ImagesPlus to reducer errors.

Comments

Sky plot

Sky plot

Histogram

Iris and the Ghost (NGC 7023 to vdB 141 area), 



    
        

            snakagawa