Focus point on Sky Watcher Equinox 100mm+Tele Vue 75mm extension tube for ZWO ASI174MM camera with Daystar Quark hydrogen and calcium-H filters

Focus point on Sky Watcher Equinox 100mm+Tele Vue 75mm extension tube:

= 74mm Quark H+Daystar interference elminator+QHY ASI174MM.
= 44mm Quark CaH+Daystar interference elminator+QHY ASI174MM.

A Couple of Pelicans

This one has taken a while. Back in July I took a picture of the Pelican Nebula that was a combination of 30 minutes RGB and about 80 minutes of Ha. The plan was to add some Oiii and Sii and turn it into a full narrowband image. Almost 2 months later we’ve finally had a clear night that has enabled me to get those 2 other channels. I managed to get an hour on each filter. Looking at the data that came out of this, it really wasn’t quite enough as both are quite weak, but patience had run out and I put it all together anyway and tried to sort out the various defects in post-processing.

So for the imgers- Oiii and Sii are both are 60x 1 minute subs, added to the 80 minutes of Ha and 30 minutes of RGB. All used gain 250 to keep the read noise down so that I could keep the subs short. In both of the images the RGB is only used for the stars.

First here’s a more naturalised version in which the Oiii and Sii are both fed into blue and green, the effect of which is to bleach the Red Ha:

Secondly here’s an SHO version. As usual it initially came out very green (because Hydrogen is dominant), and I then used the Hue and SCNR tools to distribute this out into Blue and Gold before adding the RGB stars: