Star Hopping with a Mak on an EQ mount

[eifionglyn]

I had first light since returning to astronomy last night. Picked up a 2nd hand Skymax 102 on an EQ3-2 mount.

Found the mount lovely, very smooth and very steady with the 102, and using the red dot finder had enjoyed nice views of M13 and could just about make out M57 - though it was getting lost in the moonlight somewhat. These were found by just popping the red dot over where I knew there were (ish).

Then I thought about how to find anything else. I'm used to star hopping with dob and a sky atlas. I pause for a second, wait until I see what edge of the field of view new stars appear at, and that gives me East. West is obviously 180 degrees away from East. And North is anticlockwise from West, because it's a sky map not a ground map. Rotate the atlas till it matches the view and job done, the direction to move to your next step along the hop is now obvious. This is what I used to do with 8 / 10 inch dobs, that I usually equipped with a 50mm RACI finder and a red dot or Rigel quick finder.

Should be even easier with an EQ mount right? after all the mechanics of the mount limit the direction of movements to RA and Dec, which match up with lines drawn on the sky atlas. So I leave the controls alone. New stars appear at the East edge and disappear of the West edge. This still has to be true - no mount or optics can change the earths rotation, but how does this factor in with the mirror flip caused by the star diagonal? And what effect is had by rotating the diagonal to get the eyepiece to a comfortable angle to view through. If I rotate my atlas so that East / West lines up with what I see in the eyepiece does that mean that North / South is now reversed? I think it must be. Not sure what my question is really - just trying to work it out in my own head. Can you train yourself to relate the reversed image in the eyepiece to the correct orientation in on the paper? I suppose the easiest thing would be install a 90 degree correct image finder on the 102 and use that to star hop.

[Ags]

7 minutes ago, eifionglyn said:

I suppose the easiest thing would be install a 90 degree correct image finder on the 102 and use that to star hop.

Definitely! I have an ST80 mounted side by side with my Mak 102 on my alt-az mount, and my workflow is:

1. Point red dot finder at right location

2. Locate object with ST80 (3 degree field)

3. Enjoy object with Mak 102 (1 degree field)

[Stu]

It can be quite disorientating can't it?

Basically the view with the diagonal will be left right reversed but the right way up. Not sure how further to help at this stage. When star hopping I prefer to use an Alt Az mount but I know @michael.h.f.wilkinson uses an EQ mount for visual with a C8, and he manages to star hop very successfully so may have some better advice for you.

[eifionglyn]

1 hour ago, Stu said:

It can be quite disorientating can't it?

Yep, especially when rotating the diagonal to get the eyepiece to a sensible place to look through meaning that 'up' is seldom up anymore.

[Paz]

 

Regarding maps if you have a map on tracing or thin paper and look through it from behind you see east/west flipped. If you turn the map on its side and then look through from behind you see north south flipped.

Edited May 22, 2019 by Paz

[eifionglyn]

I think I'm starting to get the hang of it.

Went out last night just after sunset to see if I could spot Mars before it set. I did not, it was either too close to the sun to be visible in the twilight glow, or was hiding behind the clouds gathering in the west, or had already set below the level of the local rooftops (or some combination of all three).

Regardless, as it got darker Arcturus was one of the first stars to become visible overhead, so I swung the scope to that, fired up Sky Safari and compared the view in the eyepiece to the app. I found I could move around and follow where I was going, up / the same, left / right reversed. Rotate the diagonal and it goes all kinds of funky, so I will make the effort to set a height for the tripod and my chair that lets me keep the diagonal vertical while still getting my eye to it comfortably. Luckily the short tube of the 102 mak is quite accommodating in this respect.

It probably already exists (can't believe I'm the first to think of it) but a 'mirror flip' display option in Sky Safari would be a massively useful thing. As would a split screen function. With a tablet one could have two zoom levels displayed side by side, a zoomed in view showing the current view through they eyepiece and a wider view showing the general area at the same time.

Or a sky atlas printed on transparencies. Hmm, Dragon's Den anyone?

[Paz]

There is a mirror flip option you can toggle in sky safari. If you tap on the top right corner of the map where it shows the size of the view there are flip options.

[eifionglyn]

1 hour ago, Paz said:

There is a mirror flip option you can toggle in sky safari. If you tap on the top right corner of the map where it shows the size of the view there are flip options.

Can’t seem to make it work. Maybe it’s only in the premium version. 

[Stu]

1 hour ago, eifionglyn said:

Can’t seem to make it work. Maybe it’s only in the premium version. 

Looks like that's the case unfortunately 

[adyj1]

2 hours ago, eifionglyn said:

Can’t seem to make it work. Maybe it’s only in the premium version. 

Are you sure? I thought this was in the free version (although now I've upgraded to 'plus', I can't check) 

In the picture below, I have tapped the '11.1 x 17.6' text to bring up the screen @Pazis talking about.

Ady

[eifionglyn]

Yeah definitely not coming up for me, on an Android phone or iPad.

 

The comparison chart at https://skysafariastronomy.com/skysafari-6-professional-astronomy-telescope-control-software-for-android.html says that Telescope Equipment Settings and Coordinate Grids and Reference Lines are two of the many features on in the plus or pro versions. Seems likely that ability to flip the display would be included in those features.

 

Now to decide if I want the android or iOS version. 

Edited May 23, 2019 by eifionglyn