Since fitting an ESATTO 2 inch motorised focuser to the Mewlon 210 and enjoying the larger FOV of the ASI1600MM Pro, I am re-visiting some old targets as I shake down the new gear and techniques.
I captured 60x60 secs of Neptune and an old favourite, Nereid a faint moon of Neptune (mag 18.7) on 24th and 27th August using the Tak Mewlon 210 and ASI1600MM.
Nereid is the third largest of Neptune’s moons, and the second to have been discovered. It was discovered on 1st May, 1949 by the Dutch American astronomer Gerard P. Kuiper (for whom the Kuiper Belt is named) using photographic plates from the McDonald Observatory in Fort Davis, Texas. It is named after the numerous daughters, called Nereids, of the sea god Nereus in Greek mythology.
Nereid has a diameter of about 340 km (210 miles). It revolves around Neptune with a period of just over 360 days in a highly elliptical orbit—the most eccentric of any known moon—that is inclined by more than 7° to the planet’s equator. Its mean distance from Neptune is 5,513,400 km (3,425,900 miles), which is about 15 times farther from Neptune than Triton. Nereid is exceedingly faint, making observations with even the largest Earth-based telescopes very difficult.
- #1 – the FOV combined for both nights showing the movement of Neptune, Triton and Nereid over that period.
- #2 – a cropped region focusing on these bodies.
- #3 - #2 annotated
- #4 - #2 with an overlay from SkyTools 4 Imaging to show the magnitudes of some of the field stars.
The ASI1600MM delivers a 29x22 arcmin FOV at 0.38 arcsec/pixel and a plate solve indicates the Mewlon 210 F11.5 with the Tak x0.8 Reducer/Flattener at the spacing I have it, gives me a fl of 2080mm at F9.9.
I am very satisfied with the ESATTO 2” Robotic Focuser and having the ability to inject automated @Focus3 “focusing runs” with The Sky X Pro, along with the Dithering option in The Sky X Pro and the Batch Processing Script in PI, when all combined have certainly breathed new life into the hobby for me. I was stuck in the 1990’s with techniques acquired in the era of small chips and manual methods.
Cheers
Dennis