184 replies to this topic

[SocalStarGazer]

Hi Cenk,

I have been following this thread without much to add, and might not still....

Your alignment issues sound a bit like what I experienced with my 5SE recently after I added a dew shield. What I found with the help of all here is that balance is important.

I have added a metal dovetail base, dovetail and a fairly heavy red dot finder to the rear of my rig. On the front is the dew shield.

I took the OTA off the mount and resting the OTA dovetail on a pencil on a table found the approximate center of gravity of my scope with my accesories. The approximate COG meant I had to put the OTA back on the mount and move it all the way forward as far as possible to have the balance point near the midpoint on the mount.

Since I have done this my goto's are very acceptable and object come into my FOV even with a 2x barlow on my 25mm ep.

I must admit that when the scope was set up as sent from the factory, my goto's were more centered, but I can live with what I am currently getting.

I might play around with the COG more by adding weight to move it and see if it helps out.

[Cenk]

It's never as easy as advertised is it ! I thought the whole alignment was going to be a piece of cake ! I even entered my precise LON/LAT. Would the GPS add on make a difference ?

Thanks on the heads up on Summer time !

[osbourne one-nil]

I can't believe I have to enter the time each session; that seems very strange.

I think the GPS would take care of the issue, but at a cost and another cable!

[Tel]

Hi Cenk,

I don't know if it will help but for what it's worth, if you look over on "Alignment Tips Here-" at the top of this forum's index page, you'll note that I wrote a text for someone at the time to help him set up a Nexstar 5SE. (It's on page 3).

I don't know how many of the aspects mentioned you've covered already but dismiss those you have.

Secondly, you do not have to change to Summer time, Daylight savings, Zone time or anything else. Keep the 'scope on Universal Time (GMT) and it's fine.

Different clock times around the world are only for mortal social and political benefit. The heavens revolve with or without them. London 12:00h. Universal Time (GMT) is still 12:00h Universal Time in New York although local clocks will tell you that it is 07:00h.

Lastly, to be "degrees out" with your GoTos and alignments, must be considered way off the accuracy these 'scopes can achieve indicating something possibly wrong in your technique.

If you let us know in detail perhaps, how you've set up your 'scope (and refer to that text of mine if you wish), I'm sure the problem(s) can be solved quickly. I think though we all need to know these aspects before any advice is given.

BTW, just my opinion but unless you envisage travelling with your 'scope far afield, a GPS is IMHO, an uneconomic option if you really analyse what it actually provides.

Best regards,
Tel

[Starlighter]

I believe that when placing the scope into the hibernation mode, the clock continues to tick. Am I wright or wrong on this?

[TonyDralle]

I believe that when placing the scope into the hibernation mode, the clock continues to tick. Am I wright or wrong on this?

I use hibernation mode occasionally when there are long intervals of fair weather (not in February!). The time does need to be reset when awakening from hibernation. Considering that it takes about ten seconds, I don't regard it as burdensome.
- Tony

[Tel]

Well not in the case of the the older N8i like mine and I'm guessing this feature, applicable to the SEs, hasn't changed. Without GPS, any new date and time have still to be programmed in after "Waking" the 'scope. With GPS the system will seek a link to provide this data automatically.

Regards,
Tel.

[Starlighter]

The instruction manual is confusing since it states that it remembers the location while in hibernation mode. Waking the scope up allows one to check the settings to make sure they're all correct. It doesn't mention that the time and date must be updated. The way it's written it sounds to me like it remembers the time, date and location. I gather from what you say that it doesn't.

[rick rian]

Like Tel, my 8i remembers location and time in hibernation mode ... I would assume (dangerous on my part) that the 8SE would do the same.

[Starlighter]

Then my 6SE should remember time and location as well since it's the same program. Right?

[TonyDralle]

My 8SE definitely does *not* keep track of the date or time while in hibernation. When it is awakened, it displays the same date and time which you last entered (I think), so the date would be intact if you left the scope for an hour or so during an observing session (as long as midnight does not occur during that time). But it definitely does not keep track of the time, which must be reentered. The 6SE is the same.
- Tony

[Tel]

Hi Rickster,

Sorry sir, I think you misread me on this one. I must admit that I don't have the opportunity to use "Hibernate" myself with any frequency but, if I remember correctly, it's the same as Tony mentioned.

I cetainly recall having to put in the time and maybe renew the date if it has changed while the 'scope was in hibernation mode. The other aspect is that above all, the OTA or entire 'scope itself for that matter, must not have been moved otherwise the "hibernated alignment" will be lost.

I think the point Tony and I were also trying to make (certainly in my opinion) is that GPS is a costly little unit which, while updating time and date (location is irrelevant because the 'scope retains this anyway) it saves almost no time at all over manually feeding the necessary information to the HC.

Merely a personal opinion though and I'm sure others have different views on GPS.

Best regards,
Tel

[Cenk]

Tel, I shall go and read the alignment section again. I thought I had looked through it the other day. So, by the sounds of it, the GPS unit doesn't actually do any alignment for you ? Just time and location and you still do your star alignment ?

What would the reasons be for being a few degrees out ? Could I have put the mount on incorrectly ?

[Tel]

Hi Cenk,

No, GPS is no magic bullet since you can certainly obtain completely satisfactory alignments without its help !

As to why your 'scope is off, I think first we all need to know in more detail how you've set it up.

For example, what is the "GoTo Approach" set to, (negative or positive)? Are your antibacklash settings satisfactory (smooth not "jumpy" at low slew speeds)? Are you using a reticular EP to align or even the "Doughnut" method to centralise your alignment stars (objects) ? What power supply are you using ? etc. etc.?

If you could provide a little more detail along these lines, I'm sure your "GoTos" can be made considerably more accurate.

Incidentally, having reset the corrector and collimated, what are the views like overall now with your 'scope?

Best regards,
Tel

[Cenk]

Tel,

I haven't changed any of the settings. Factory defaults. Goto approach and antibacklash are untouched. What should they be ? I use the 25mm Celestron Plossl that came with the scope. I use a DC adaptor to plug my scope into mains, batteries don't last very long. Haven't tried Doughnut method.

Views, my scope appears collimated, tested that far, I thinkmy scope dewed up last night, I couldnt really tell you exactly about its performance. Things looked hazy.

[osbourne one-nil]

Mine dewed up within half an hour last night and I had a dew shield on, so I think you might be right.

[Cenk]

What's the solution to the Dew problem ?

[osbourne one-nil]

You'll find loads of threads on here about dew, and it seems to be at least the addition of a dew shield, which you could make yourself or buy a custon one for about £30 and possibly some dew prevention heater-type tape, although in Kent it might not come to that like it does up here.

My understanding of dew is it forms when the surface of the telescope drops below the dew point of the air, so you have to either have to provide a bit of insulation in the form of a dew shield or warm the corrector plate so it doesn't ever drop that low.

It's so bad here, I once had the primary on my f5.3 12" newtonian dew over. That's a 5ft tube acting as a dew shield!

[Tel]

Quick one here Cenk !

Depending on your power source (I think you said you were running a mains adapter but can't remember) and just to keep you up and running for the time being : a mains or better still a 12V portable (camping) hairdryer.

Gentle application of heat, mind, and make sure that you blow it through first in case there's any hair in it which might be blown onto the corrector !

You can always make up your mind over this or that "Dew Zapper at a later date !

I'll try to be back on the alignment front as soon as possible but it may well be later this afternoon from my current commitments.

Best Regards,
Tel

[Tel]

Hi Cenk,
I've just had a look at that "Alignment Tips Here ---" I wrote regarding the setting up of that 5SE and I suggest, in the meantime, you take a look if you haven't already done so.

Basically I think it will easily read across to the setting up of a 6SE with perhaps one off the top of my head exception, that the altiude "GoTo Approach" might do better set to "positive".

Forget factory settings by and large. Concentrate on making sure you lat./long are correct, that when you come to it, you enter the correct time (UT) and date, (remember ! American format only!), and as to antibacklash, you will need to get this right by working at it. There are no standard settings for this. Each individual 'scope seems to be different although I can tell you that the altitude axis is much more sensitive than the azimuth.

Also with regard to the altitude axis, it seems that keeping the antibacklash figures low pays dividends.

Must now go ! Read throught the text, if you will, and please come back if you wish with any related questions.

Best Regards,
Tel

[Cenk]

Ok. I will try on both Dew and Alignment and come back.

[rick rian]

Hi Rickster,

Sorry sir, I think you misread me on this one. I must admit that I don't have the opportunity to use "Hibernate" myself with any frequency but, if I remember correctly, it's the same as Tony mentioned.

I cetainly recall having to put in the time and maybe renew the date if it has changed while the 'scope was in hibernation mode. The other aspect is that above all, the OTA or entire 'scope itself for that matter, must not have been moved otherwise the "hibernated alignment" will be lost.

I think the point Tony and I were also trying to make (certainly in my opinion) is that GPS is a costly little unit which, while updating time and date (location is irrelevant because the 'scope retains this anyway) it saves almost no time at all over manually feeding the necessary information to the HC.

Merely a personal opinion though and I'm sure others have different views on GPS.

Best regards,
Tel

Mornin' Tel,

Sorry for the confusion on my part ...

Like Tel, my 8i remembers location and time in hibernation mode ... I would assume (dangerous on my part) that the 8SE would do the same.

In my quote above I made some assumptions that I should have clarified ... a pox upon me.

First, when I last used the Hibernate utility, I had my 8i set up in my back yard for a multi-day session. It was placed on the tripod and not moved for that period. I have the GPS unit attached and thus when I "woke-up" the unit my time and date were 'automatically' entered. I guess I should have mentioned that. (sometimes I can be such an idiot!)

Sorry for any confusion.

I think the point Tony and I were also trying to make (certainly in my opinion) is that GPS is a costly little unit which, while updating time and date (location is irrelevant because the 'scope retains this anyway) it saves almost no time at all over manually feeding the necessary information to the HC.

Agreed.

Now back to our regularly scheduled program ...

[Cenk]

Just fitted myself an outside power socket ! This thing eats batteries. Now it's cloudy

[Tel]

Hi Rickster,

I think we've laid this one to rest if you know what I mean !

In fact in MY confusion (warned ya !) I think I might have sent you the same PP twice ! (LOL).

Best regards,
Tel

[Cenk]

Tel,

Can you help with getting rid of some cloud cover ? You seem to be very good with everything else !