gorann

This is what Wiki writes about this object: NGC 4490, also known as the Cocoon Galaxy, is a barred spiral galaxy in the constellation Canes Venetici. It lies at a distance of 25 million ly from Earth. It interacts with its smaller companion NGC4485 and as a result is a starbust galaxy. NGC 4490 and NGC 4485 are collectively known in the Atlas of Peculiar Galaxies as Arp 269. Caught over two recent nights with my Meade 14" LX200R (f/10 so FL 3550 mm) and Sony A7s (run at full frame and ISO3200) on the EQ8 (Lodestar X2 and ZWO OAG). 153 x 3minutes = 7.65 hours with a bit of moon around. PS. I have to tell you a bit about the scope I used for this and some other recent images. About a year ago I by chance saw an advertisement on the general buy&sell site in Norway for a 14" f/10 Meade LX200R OTA and the seller was only a few minutes away from my house. LX200R ("R" for Ritchey-Chretien) is the original name for what Meade after losing a court case had to rename "ACF". I found the price quite reasonable (about 2500 Euro) for such a big scope but from what I had read about astrophotography, imaging with a 3.55 metre focal length scope like this one is extremely challenging and bound to be a big disappointment. My main interest is imaging, but I still could not resist having a look at it, and after seeing that big and dusty (only on the outside) scope tucked away in an attic, I was sold and I just had to buy it. I brought it across the border to my weekend house (once a small farm) in Sweden where light pollution is absent and where I had built my obsy. I soon realized that it would not fit under my obsy roof, and as it weighed 40+ kg, occasionally exchanging it for my refractors was not an option. So I decided to build a second obsy where I could put it on my old EQ8, that had been retired and was tucked away in my garage after I got my Mesu200 mount. My thought was to use it visually and in any case I did not have any camera with big enough pixels to match the focal length of a 14" SCT. When the obsy was built, and the big SCT was sitting there on the EQ8, I could not resist trying to do some imaging, and to my surprise, the old EQ8 and the big scope worked very well together. I have never had eggy stars with this set up and as long as seeing is relatively good, I get quite decent guiding, often around 0.4 "/pixel. So now I have also invested in a dedicated camera for the big SCT: a Sony A7s, a full frame APS camera with 8.4 µm pixels that I found on ebay and had JTW in Holland to full-spectrum modify. Now the new surprise was that the SCT fills essentially the whole 24 x 36 mm frame (only darkened at the very end of the corners) with nice round stars - and not very bloated stars as often seen with STCs. So this bargain scope made in the early years of this century in the US (before Meade was bought up and moved manufacturing to Mexico and then China) is now my prime galaxy hunter, and I like her more and more!

Interesting thread. I now run two obsys next to each other, one with a Mesu200 and a double Esprit rig (150 + 100 just like Dave but I have them side by side) and the other with my old EQ8 and a very heavy (40+ kg) Meade 14". I now have OAGs on both (the new ZWO on the EQ8 and a TS on the Mesu). Lodestar X2 on both. My main experience now is that I get very similar RMS values from the mounts and they follow each other tightly depending on sky conditions. So, around 0.4 " RMS on good nights and considerably worse on bad seeing nights. Recently moving from a ST80 guide scope to OAG for the Mesu made a big improvement - before that I had consistently better guiding on the EQ8 which was a bit of a disapointment, but now they are the same. I would have expected the Mesu to beat the EQ8 but I think that my atmosphere so far have not been able to tell them apart - still waiting for that magical night I did add that extra screw to the TS guider - in the original version the stalk was quite wobbly. I do worry that the TS OAG somehow leaks in light since I have had some nights with an unexplainable gradient that I never seen before after I moved from guidescope to the TS OAG. Could that be an issue?

I will get back to these one less windy night when my 14" would not wobble so much (I need 0.3"/pix guiding and not the >1 that I had last night), and then maybe even get fairly close to Adam's resolution. With 3.5 m FL you really need tight guiding. Last night the "widefield" of my Esprit saved the night and not even Hubble can compete with that FOV😉.

Yes Dave, quite a nice bunch and thanks a lot!

Thanks a lot Michael!

For some reason these lovely galaxies seem to be rarely imaged (at least when I search Astronbin). Here are data from last night. The night was very clear and SQM showed 21.5, but it was quite windy. Most of it was collected with my Esprit 150 with ASI071 on the Mesu 200 (33 x 10 min at gain 200) which took the gusty winds quite well. About 50% of the data in NGC4274 and NGC4278 are from my 14" Meade (with the Sony A7s) on the EQ8, which due to its size and enormous dew shield was fighting more with the winds. Totally 10.2 hours. There are so many galaxies in there that there should also be a plate solved annotated image for the major ones but that is for later unless some volunteer to do it. Time for dinner and to find new galaxies to point at tonight!

So a dying galaxy. Very interesting even if it must be the least impressive galaxy around😉

Thanks! Yes, the 14" images were reduced to the size of the Esprit image, but you can always zoom into the image. Here is what two of tha galaxies looked like with the 14":

Three galaxies in Draco caugth during recent nights with two scopes. Esprit 150 with ASI071 (on Mesu 200) caught the starfield and a bit of the galaxy data (57 x 5 min at gain 200) and most of the data for the three main galaxies were caught with my 14" Meade and Sony A7s on EQ8 (233 x 3 min at ISO3200). So, a reflector - refractor mix with two colour CMOS cameras, and totally 16.4 hours. There are surprisingly few images of these galaxies - maybe becasue they are quite distant (=small).

Thanks a lot Alan!

Excellent image Dave! I did image the same group with my Esprit 150 a year ago, and seeing your image make me think that I may have been a bit too promiscuous with the colours (https://www.astrobin.com/394768/K/). Similar level of resolution but then we have the same magificient scope. Glad to hear that you have a spell of clear skies - we need something positive these days! I will hopefully get 2-3 clear nights from Friday.

Like you I prefer RGB or images with a plaette looking like RGB even with some NB added, and you clearly succeded! Great image!

If you have a car battery you can allways hook it up to that until something more practical arrives. Just check that you get the polarity right. ZWO recommends a devise that can deliver 5 A since the camera may draw more than 3 A. A 2 A fuse will brun up very soon, as yours did. You can burn the camera with too high voltage but you cannot burn the camera with amperes - it will draw the amperes it needs. PS. I would stay out of cheap chargers ment for things like razors since they may deliver a rather dirty (i.e. fluctuating) voltage that is not good for electronics.

Glad that you also see it - maybe the name could catch on

Excellent image Dave! I like everything, including the framing.

A very faint nebula from the Shapeless catalogue and possibly the last one I image this season - as it is time to focus everything on galaxies. In my 3.3 hours of RGB data it was nowhere to be seen, it only appeared after I added 3.3 hours of Ha. It has no name what I know but it reminds me of some kind of ugly monkfish about to swallow a blue star. The nebula can been seen near the top edge of Tom's @Tom OD mega mosaic of Cassiopeia. Data collected with my Esprits side by side on the Mesu. Esprit 150 with ASI071 caught 38 x 5 min of RGB (gain 200) while the Esprit 100 with ASI1600 caught 13 x 15 min of Ha (gain 139, Baader 3.5 nm). So totally 6.6 hours of photons collected before the northen obsy wall got in the way. Because I found it to be quite faint I also kept the image quite dark.

Thanks, much appreciated!

Thanks a lot Jeremy!

These are two relatively small (i.e. distant) and rarely images galaxies in Draco towards which I pointed my 14" SCT f/10 (so 3550 mm FL) on Saturday night (sitting on the EQ8). I had the Sony A7s on ISO 3200. A nice clear night with SQM 21.45 and guiding was rather good, around 0.4"/pixel. 132 x 3 min, so totally 6.6 hours. Processed in PI & PS. Now clouds are back....

Thanks Wim, I am happy you like my restrained processing.

Thanks a lot Michael, much appreciated! Yes, I now try to go for less common objects - and I entertain myself finding them on various net resources during cloudy nights.

Thanks Alan! Sony A7s is quite a different camera. I have been drewling about one since it came about five years ago, but it was too expensive. Now when Sony has produced a Mk II and MK III version, the original (with still the same chip) has become affordable on ebay (where I got mine). The chip is a low light chip with very big pixels, so only 12 Mpixel even if it is a full frame APS. It is aimed a evening and night photography and the electronics is in a league of its own. ISO6400 is nothing for it, max setting is over ISO 400 000 if I remeber it correct, but at that setting it is very noisy.

Thanks Dave! I think you are slightly wrong about their location - these ones are in Leo. You may be thinking about some other peculiar galaxies.

NGC 3227 is an intermediate spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies, these as Arp 94. The data was collected over two recent nights and is a mix of 2 and 3 min exposures at ISO 3200 and 6400 as I am still testing out using the full spectrum modded Sony A7s on the 14" SCT (Meade LX200R). Air temperature was a few centigrees below zero which probably helped keeping noise down. This full frame 12 MP APS camera have large 8.32 µm pixels, so it is a relatively good match (still a bit oversampling) for the 3.55 m focal length of the SCT. This 40 kg scope is sitting on my EQ8 which handles it quite well. OAG with Lodestar X2 and guiding around 0.4 "/pixel which is almost sufficient (my pixel scale is 0.49"/pixel so it would be nice with guiding below 0.3"/pixel and the EQ8 can probably do it but the sky is rarely that steady). SQM was good, around 21.3, which helps when hunting relatively distant galaxies. Totally 8.9 hours of data. Cheers Göran

We have had a spell of clear nights here and these days I have plenty of time for imaging. So I have been both hunting galaxies and continued collecting interesting objects in the Sharpless catalogue. Here are two of them in the constellation of Camelopardalis, the bigger one in the centre is Sh2-207 and the smaller one to the left is Sh2-208. The small star cluster seen in Sh2-207 is Mayer 2. The big area of nebulosity covering the left side of the image has as far as I know no number or name, possibly becasue it is very faint. Still it has some nice structures. Almost all the red signal was picked up by the Ha filter and there is only a faint indication of Sh2-207 in the RGB data. Sh2-207 was once thought to be a planetary nebula, given the designation PK 151+02 1, but this is probably not the case. These nebulae are 13 000 - 15 000 ly away Ha was collected over two clear nights (SQM 21.3) with the Esprit 100 and ASI1600 (40 x 15 min at gain 139, Baader 3.5 nm Ha filter) and RGB with the Esprit 150 and ASI071 (125 x 5 min, gain 200), sitting side by side on the Mesu 200. Totally 20.4 hours which is longer than I usually image, but this are is quite faint.