During my first viewing of Jupiter a few weeks ago just before sunrise, I wondered to myself whether it would be visible after sunrise. Are there any planets or other objects (besides the sun and moon) that can be seen during the day, besides during a solar transit. Venus seems so bright sometimes that I wonder if it can be seen through a scope in daylight.
Hi luke, yes, I've looked at Venus many times during daylight and to be honest, I actually prefer it! (Less glare and if you use a blue filter in particular it's even better)...I've never looked at anything else, except the moon, but am sure if you could line it up, Jupiter would b3 bright enough to squizz....
Currently, Venus can be seen with just your eyes in the last hour or two before sunset. However, finding it first with binoculars makes it much easier.
I have also seen Jupiter during the late afternoon with an 80mm telescope and have even followed one of the eclipses as it moved across the planet.
Before opposition, Mars is also another planet that can be viewed for a few hours after sunrise.
I have even seen Sirius with the unaided eye by following it before sunrise. Admittedly, it was only just after sunrise, but the sun was shining on the wall next to me. The moment I looked away, I could not find it again, but it was still visible in a 4” Astroscan telescope that I then owned. I have also easily seen Canopus in small telescopes after sunrise.
I cheat a bit here, I usually find them in a telescope that tracks before sunrise, and let the mount do most of the work.
Luke, if you have a scope with setting circles and know how to use them safely (or GOTO) - without pointing the scope at the sun - you can find 1st magnitude stars in daylight with a 6" or 8" reflector.
The only way to do this safely IMHO is to set the scope up in the shade, e.g. under a carport, in a garage or in the shadow of a tall building - to protect you from pointing it accidentally at the sun.
I have seen ALL the inner Planets plus Jupiter and Saturn during the day through an 8" telescope, Venus can be seen naked eye easily if you know where to look. I havent tried stars during the full Daytime (except our closest star) Give them a go, the thrill of the hunt is sometimes more rewarding than the catch at the end.
Thanks for all the replies.
Wow, I'm surprised that mercury could be seen through a scope in daylight. Is the detail of the gas giants lost with daylight viewing?
Didn't some poet talk about the veil of night falling over the earth. To me its the opposite - the veil of daylight preventing us from seeing the stars. But now I cant wait to see if I can see Jupiter during the day. I must admit, I think a thin crescent of the moon in daylight is more beautiful than at night.
I haven't done any serious scope viewing of the planets during the day but at various times I have viewed Venus, Jupiter, Comet McNaught, and Antares with the naked eye and/or binoculars.
Safest way to do it (particularly if using a scope or binoculars is to setup with the sun occluded by some like the eaves of your house.
Looking for Venus yesterday, Stellarium showed it would be directly overhead at my location (Albion, Brisbane) at 14:47. I just set my scope pointing straight up and there it was. Had another go today with a similar predicted time overhead. Noticed from Stellarium that Venus was closely following track of the Sun. I set up a bit early today at 13:45, aimed my scope to have the Sun directly behind and then 'dropped the nose' to scan down. And there she was again.
Two or three Astrofests ago, Jupiter was right next to a new Moon crescent. I remember people having a look throughout the day.
In the days before GPS, land surveyors often used the observed positions of stars and planets to determine geographic location.
The brighter planets and stars can be seen using the small aperture telescope used in surveying instruments, although atmospheric pollution is making this more difficult in modern times.
The Star Almanac for Land Surveyors contained sun and star ephemeris information for position calculations. Moon and planet data could be found in the Nautical Almanac.
The direct sunlight on a telescope will cause nasty tube currents. Some form of shade will help. The following paper describes a test of the 200" Hale telescope for daytime observations. http://trs-new.jpl.nasa.gov/dspace/b.../1/06-0218.pdf
This telescope actually worked better after a bake in the sunlight.
A long dew shield will improve telescope views by reducing scattered light. A long cardboard tube on the finder will make is easier to locate targets.
I was lucky enough to have good seeing conditions over the weekend, so Just as the sun dropped below a nearby escarpment, I swung the scope around to the western sky at about 45 degrees and scanned around. Found venus fairly easily through the finderscope, and then got nice views with a 12mm Delos eyepiece. The following morning, I got up at 5am to see Jupiter - there was a bit of high cloud around but I got good views. I tracked it with the hope of following it after sunrise, but fog and mist rolled in.
Hi Patrick,
Its incredible to think that daytime astronomy was used by surveyors before GPS. I suppose they would have needed some training in astronomy. Did they use their theodolite to look at the stars?
If they didn't have accurate time from a chronometer or radio time signal, then surveyors had to use basic celestial navigation.
You can get a star position quite well using a theodolite, but you have to do alt-az to eq transformations using tables or even pencil and paper.
A marine sextant is good for measuring star - planet angular separation directly.
With some effort, and good weather, an accuracy of several tens of meters is possible. A modern differential GPS station is about a thousand times more accurate.
I would expect that some of the older members here have experience in practical celestial navigation.
You can get free books on the theory and links to ephemeris data to try it yourself:
Its incredible to think that daytime astronomy was used by surveyors before GPS. I suppose they would have needed some training in astronomy. Did they use their theodolite to look at the stars?
Yes while it is possible to use conventional theodolites, and there were (are) astronomical theodolites with specific adaptations.
If nothing else was available as a reference to determine azimuth, surveyors sometimes used the sun by fitting a solar filter on the front of the telescope and using an almanac to determine its azimuth by date and time of day, though you also need an accurate clock for this, and corrections must be made for atmospheric refraction. Several measurements are usual too, both as a check and to reduce the probable error in the overall measurement compared to a single measurement,
Typical uses:
- determining time,
- determining the clock correction (it was usual to measure the error between actual time vs what a clock showed, and to measure the drift rate over several days, weeks, or even years);
- determination of latitude,
- determination of longitude,
- simultaneous longitude and latitude determination using two stars;
- determination of azimuth (to some distant reference object);
- various corrections to be applied for refraction, non-spherical earth, etc...
As regards accuracy... back in the 1970's-90's for those who participated in an experiment to measure the solar diameter accurately using Bailey's Beads at a total solar eclipse, USNO requested you put a peg in the ground under your telescope and take a photo of it (so it can be found again). If your data was good USNO surveyed your location to measure it's absolute position using an astronomical theodolite to one foot, better than GPS. Being USNO no doubt they had the best gear in the business, though I don't know what that was.
I would expect that some of the older members here have experience in practical celestial navigation.
Haha….that's how I got interested in Astronomy in the first place. A few decades away now.
Not to sure of the value of looking at anything other than the Sun (with a Badder Solar Film fitted of course) during the daytime but good luck Luke.
Matt
To reply to the first question: I have cheated, and used my computerised mount to start the ball rolling, but I have seen all the naked eye planets (including Saturn) in the middle of the day with my 4" scope. Venus is quite bright naked-eye, and Jupiter is visible naked-eye within a few hours of sunset/sunrise if it is about 90 degrees from the sun. Mercury is also surprisingly bright, but I don't think you will see it naked eye as it is always too close to the sun, in the brightest part of the sky.
A good challenge is to see how faint you can see stars with your scope in daylight! Through my 4" scope I can see 2nd magnitude stars and even a bit lower. I have split alpha Centauri, alpha Crucis and even Castor in daytime.
A good time to try to spot Venus naked eye is when the crescent moon is nearby. I once showed a Year 1 class the moon in daytime, and some of them said "There's a star next to the moon!" (without my prompting): it was Venus.
You might want to try this in 2 days time when the moon is about 15 degrees North of Venus.
All the best,
Dean
Just on Thursday I saw Venus at 3pm by following the moon. It would have been 8 degrees away from it but by blocking the sun and scanning around the moon, i found it within 2-3 minutes. Was quite cool to see something other than the moon and sun in the sky!
I would still like to point my scope at it but finding it would be a pain...
Seeing is usually worse during the day, but with Mercury you have a tradeoff between seeing and being able to view it away from the horizon murk. Many of the old time observers did most of their Mercury viewing during daylight.
Geoff
Yes you can view many things in the day time. The sun obviously, with a filter of course. Other things like the Moon, Jupiter, Venus and even some bright stars can easily be seen during the day. I guess the main thing in the day is the sky itself has a certain level of brightness. While I am not sure exactly what that is it limits what you can and can not see in the day. As mentioned by others though please be careful not to accidently look at the Sun with an un filtered scope. I know no one would do this on purpose but it can be done accidently and can not be cautioned enough.
Here are some single thru-the-eyepiece shots taken from Europe and Australia during the past 18 months or so. Aldebaran, Jupiter, Venus, Vega. Note the annular phase in the after-transit Venus shot. No stacking, no tracking, no guiding, just hiding (of the scope in the shade in the case of Venus) . So please excuse the IQ & gunk on the glass. I mostly do visual. The Venus views were obtained at 3 and 1.5 degrees elongation, respectively, so extreme care was needed. Gives a rough impression of what you may see when skies are clear. In all cases, the Sun was at least 20° above the horizon. The point of all this (this is to you Matt) was sheer fun in being able to look out into space in broad daylight with the scope pointed at a blue featureless canvas. And, locating daytime celestial objects with a 60mm refractor, only based on knowing whereabouts they should be.
. So please excuse the IQ & gunk on the glass. I mostly do visual. The Venus views were obtained at 3 and 1.5 degrees elongation, respectively, so extreme care was needed. Gives a rough impression of what you may see when skies are clear. In all cases, the Sun was at least 20° above the horizon. The point of all this (this is to you Matt) was sheer fun in being able to look out into space in broad daylight with the scope pointed at a blue featureless canvas. And, locating daytime celestial objects with a 60mm refractor, only based on knowing whereabouts they should be.
