Rosette Nebula (L-eNhance filter, 95% Full Moon) [Explored #73]

I've always avoided doing DSOs in Moonlight but a while back, I bought an Optolong L-eNhance Triband filter which can be helpful in reducing light pollution and stray Moonlight - it predominantly passes 3 narrow band widths centred on:

 

Hydrogen Alpha: Red, 656.4 nm

Oxygen III: Green, 500.7nm

Hydrogen Beta: Green-Blue, 486 nm

 

The filter is certainly more opaque than my standard IDAS P3 light pollution suppression filter. Usually my flats are exposed at 1600ms but for this filter it was 6500ms at 0 gain. Autofocus and plate solving exposures were 4s at 578 gain.

 

The raw image was lacking in contrast - not surprising given the Moonlight but I've used curves enhancement and local contrast enhancement in PixInsight to improve that. I haven't altered the colour palette as this was a first test for this filter.

 

Technical Card

480/80mm f/6 Altair Starwave triplet refractor.

Altair Planostar 1.0 x FF with 2 inch L-eNhance filter

ZWO ASI2600MC; 39 x 360 second subs, Gain 100, Offset 25, Temp = -15c.

 

EQ6 pro mount with Rowan belt drives. EQMOD control. Primalucelab Sesto Senso electronic focuser.

 

Session control; SharpCap 4.0 on laptop with WiFi link to IPad.

Automated plate solving GOTO.

Automated FWHM multistar focusing every 16 frames. +/- 500 steps at 2s and 578 gain.

 

 

20 dark frames

50 flat frames (electroluminescent panel, 6500ms exposure @ 0 gain).

 

Post processed in PixInsight 1.8.9.

 

Light Pollution and Weather:

SQM (L) not recorded - 95% Moon

Session ended by cloud, target was also very near roof level.

 

Polar Alignment:

Resumed from previous Park.

Error measured by PHD2= 0 arc minute.

RA drift + 2.44 arcsec/min

Dec drift - 0 arcsec/min

 

Guiding:

PHD2 guiding with ZWO ASI290mm/Altair Starwave 206/50mm guider. Every 4th sub dithered.

RA RMS error 1.1 arcsec

Dec RMS error 0.82 arcsec

 

Astrometry:

Resolution: 1.612 arcsec/px

Rotation: -87.819 deg

Observation start time: 2023-02-07 20:41:29 UTC

Observation end time: 2023-02-08 01:09:49 UTC

Focal distance: 481.13 mm

Pixel size: 3.76 um

Field of view: 2d 9' 37.7" x 1d 41' 33.2"

Image centre: RA: 6 32 17.164 Dec: +4 58 40.33

Done