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I thought I would share with you my first hand experience of the Skywatcher ED100 Pro Esprit Telescope, I have only had it a few months, but so far I am extremely happy with the results, it is so sharp and the contrast is very high.
I live in a small town, Stowmarket, Suffolk, UK, where the light pollution is not to bad, but still I have to be cautious with the direction I choose to point the telescope. All my astrophotography is done from the back garden on my patio.
I have had a few different telescopes over the years, but I always found myself moving more and more into astrophotography, so after some research I selected the Skywatcher ED100 Pro Esprit, as many of the other users had commented on the sharpness and contrast. As I wanted to focus on more wide field astrophotography the F5.5 speed giving 550mm seemed the right choice, I also use an ED50 Skywatcher Guide Scope with an Altair Astro ASI130mm camera for the guiding and of course PHD2 software, all mounted on my Skywatcher HEQ6 mount.
Here is a shot of the Andromeda Galaxy, 20 x 30s stills at ISO 800 on my Sony A7Rii, no filters just RAW images processed with Photoshop, Stacked Mean option. I used the Trevor Jones video on his BackyardAstro You Tube page for processing DSO's and it seems to work very well. What you will see from the image is just how sharp it is, something that really surprised me when I processed the images.
This has inspired me to spend more time outside in the garden to photograph more objects, plus I have recently purchased an Astronomic CLS Filter for my Sony A7Rii, so I am looking forward to using this to see if it improve the contrast. I will keep you informed.
Also I am looking forwarded to trying my Olympus EM1 MK2 camera, yes I know it does not have the capabilities of the Sony A7Rii for light gathering, but it does have a really clever mode where it can stack the images in camera to reduce noise, so I will also let you know how this went as well.
Distance from Earth - approx 2.5 million light years
After spending ages getting a decent polar alignment, the clouds were on their way in so I only had a small window of opportunity remaining. This was my first real run with the new setup (minus the ST80 and ZWO ASI120 as i was having issues there) and I almost gave up. SO glad I didn't!! Focus was off a bit though I think and I've definitely over-processed
f / 5.6 @ ISO 800
21 x 30 second subs
Stacked in Sequator. Very quick minor crop and global edits in LightRoom. No darks/flats/offsets
This is my first astrophotography with my own scope (and first light for this scope). I've always been fascinated with this galaxy, and it was my childhood dream to capture it. It finally happened ;-)
You'll find all the technical details on the description on flickr.
Overall it's the first light of my skywatcher Quattro 250mm/1000mm f4, NEQ6, with an unmodded Canon 6D.
Integration time: 1h59
Processed with PixInsight.
link to flickr for the full resolution and description:
By Ben the Ignorant
Funny, the physical laws of reflection, refraction, scattering, diffraction, etc, are similar for sound waves and light waves, but the resemblance does not stop there. Listening to various car loudspeakers, I found the minimal diameter for an acceptable sound is 70mm, and that's also the smallest diameter for a satisfactory telescope in my view. 80mm grant a little more resolution in both, and 80mm is a very popular diameter in compact scopes or compact radios, at least the older ones.
They make 90mm scopes to get some extra oomph, and the 90mm loudspeaker begins to issue more discernible bass, so much so I keep one from an old radio my father bought in the 70's, not knowing what I'll do with it but the bass, checked that when plugged to a guitar amp, is noticeable enough despite the size. Then the standard louspeaker size in non-toy stereos is 100mm, and the standard refractor size to get good resolution and power is also 100mm. There must be a reason if so many observers buy that many expensive 4-inch apos, but not nearly as many buy tighter apertures for comparable sums.
Following the same progression, monitors in studios have 125mm to 130mm loudspeakers (that need to be complemented by a tweeter because the similarity cannot be total between light and sound), and these diameters are also the ones that provide deeper resolution on planets. 150mm approaches real power in telescopes, and 150mm is also the entry-level size for a guitar amp, like my 15 watt Fender Frontman, which does not lack bass despite its handbag format (WonderWoman's kinda big and heavy handbag).
200mm is quite enough for most observers, resolution-wise and power-wise, which happens to match the size of more serious amps. I have a modded Stagg 20w 200mm guitar amp and an Ampeg 20w 200mm bass amp, both are plenty large enough to deliver a full sound in their range. There is a reason if so many 8-inch Schmidt-Cassegrains and newtonians are in use everywhere!
Then the 10-inch scopes are heavier, but not unbearably so, and the 10-inch loudspeakers also deliver the near-maximal power and resolution for an amp that remains not hard to carry around. 12-inch scopes deliver enough light and detail to satisfy most everyone; again, the equivalent 12-inch size amps give out enough frequency range and raw power to please the vast majority of players. Size and weight become an issue in both cases, but not enormously so.
And lastly, the ultra-large 15" amps or 15" to 16" scopes start another league in power and resolution but they both become equally difficult to transport.
Not quite apples and oranges in my opinion, does it seem like a coincidence to you?
NGC 205 in Andromeda; often imaged, but rarely noticed, it seems. I decided to put it centre stage.
In most images, this elliptical galaxy shows no details. But there are actually very subtle dark dust bands near the center, and there's also a very weak tidal stream that ties it to its larger neighbour.
Imaged in November of 2017
Equipment as in my profile
L: 14 x 180 s, at - 30 C, gain 0
RGB: 6 x 300 s each
Integration time: 2.2 hours
(click on image to enlarge)
A reprocessed version with a little more detail in the core is posted further down.