Messier 78: First Light: Esprit 120 ED
First Light for my Esprit 120 ED scope and I gave it a favourite but difficult target of a black object against a black background!
Its only 11 x 5 minutes integration and this target needs several hours to bring out the subtleties but overall pleased with optics, flats and darks.
I had some problems with my electronic focuser slipping and causing problems with both "manual" and auto-focusing routines but hopefully a little bit of bench testing will sort that.
I think autofocus would have got the stars a little sharper than my "manual" efforts here.
i think the subs are also good enough to bank and add to any future sessions on this target.
Technical Card
840/120mm f/7 SkyWatcher Esprit 120ED triplet refractor.
SkyWatcher 1.0 x FF with 2 inch IDAS LPS P3 filter
ZWO ASI2600MC; 11 x 300 second subs, Gain 100, Offset 25, Temp = -15c.
EQ6 pro mount with Rowan belt drives. EQMOD control. Pegasus Astro Focus Cube electronic focuser.
Session control; SharpCap 4.0 on laptop with WiFi link to IPad.
Automated plate solving GOTO via ASTAP (5 secs exp at Gain 643)
Automated FWHM multistar focusing every 11 frames. (5 secs exp at Gain 643).
34 dark frames
49 flat frames (electroluminescent panel, (2600ms exposure at Gain 0).
Post processed in PixInsight 1.8.9.
Light Pollution and Weather:
Gusts of wind up to 21km/hr
SQM (L) 19.42 at 2130 hrs
Session ended by focuser clutch slipping during autofocus. I probably should have continued but was concerned about electronic focuser performance.
Polar Alignment:
PoleMaster alignment
Error measured by PHD2= 0.7 arc minute.
RA drift + 2.65 arcsec/min
Dec drift + 0.2 arcsec/min
Guiding:
PHD2 guiding with ZWO ASI290mm/Primalucelab
240/60mm guider. Every 4th sub dithered.
RA RMS error 1.6 arcsec
Dec RMS error 1.02 arcsec
Astrometry:
Resolution: 0.900 arcsec/px
Rotation: 4.005 deg
Focal distance: 862.09 mm
Pixel size: 3.76 um
Field of view: 1d 2' 27.8" x 1d 16' 35.3"
Image centre: RA: 5 47 15.781 Dec: +0 11 30.53
Update: the focuser problem seems to have been a loose ratchet on the focuser - it has been replaced.
Messier 78: First Light: Esprit 120 ED
First Light for my Esprit 120 ED scope and I gave it a favourite but difficult target of a black object against a black background!
Its only 11 x 5 minutes integration and this target needs several hours to bring out the subtleties but overall pleased with optics, flats and darks.
I had some problems with my electronic focuser slipping and causing problems with both "manual" and auto-focusing routines but hopefully a little bit of bench testing will sort that.
I think autofocus would have got the stars a little sharper than my "manual" efforts here.
i think the subs are also good enough to bank and add to any future sessions on this target.
Technical Card
840/120mm f/7 SkyWatcher Esprit 120ED triplet refractor.
SkyWatcher 1.0 x FF with 2 inch IDAS LPS P3 filter
ZWO ASI2600MC; 11 x 300 second subs, Gain 100, Offset 25, Temp = -15c.
EQ6 pro mount with Rowan belt drives. EQMOD control. Pegasus Astro Focus Cube electronic focuser.
Session control; SharpCap 4.0 on laptop with WiFi link to IPad.
Automated plate solving GOTO via ASTAP (5 secs exp at Gain 643)
Automated FWHM multistar focusing every 11 frames. (5 secs exp at Gain 643).
34 dark frames
49 flat frames (electroluminescent panel, (2600ms exposure at Gain 0).
Post processed in PixInsight 1.8.9.
Light Pollution and Weather:
Gusts of wind up to 21km/hr
SQM (L) 19.42 at 2130 hrs
Session ended by focuser clutch slipping during autofocus. I probably should have continued but was concerned about electronic focuser performance.
Polar Alignment:
PoleMaster alignment
Error measured by PHD2= 0.7 arc minute.
RA drift + 2.65 arcsec/min
Dec drift + 0.2 arcsec/min
Guiding:
PHD2 guiding with ZWO ASI290mm/Primalucelab
240/60mm guider. Every 4th sub dithered.
RA RMS error 1.6 arcsec
Dec RMS error 1.02 arcsec
Astrometry:
Resolution: 0.900 arcsec/px
Rotation: 4.005 deg
Focal distance: 862.09 mm
Pixel size: 3.76 um
Field of view: 1d 2' 27.8" x 1d 16' 35.3"
Image centre: RA: 5 47 15.781 Dec: +0 11 30.53
Update: the focuser problem seems to have been a loose ratchet on the focuser - it has been replaced.